diff --git a/src/modules/bootloader/main.py b/src/modules/bootloader/main.py
index cbb7aa9f1..3b4c9e554 100644
--- a/src/modules/bootloader/main.py
+++ b/src/modules/bootloader/main.py
@@ -215,7 +215,7 @@ def prepare_bootloader(fw_type):
                 boot_p = boot_device[-1:]
                 device = boot_device[:-1]
 
-                if (not boot_p or not device):
+                if not boot_p or not device:
                     return ("EFI directory \"{!s}\" not found!",
                             "Boot partition: \"{!s}\"",
                             "Boot device: \"{!s}\"".format(efi_directory, boot_p, device))
diff --git a/src/modules/fstab/main.py b/src/modules/fstab/main.py
index d85dba9ff..8d096017b 100644
--- a/src/modules/fstab/main.py
+++ b/src/modules/fstab/main.py
@@ -56,9 +56,11 @@ def is_ssd_disk(disk_name):
     :return:
     """
     filename = os.path.join("/sys/block", disk_name, "queue/rotational")
+
     if not os.path.exists(filename):
         # Should not happen unless sysfs changes, but better safe than sorry
         return False
+
     with open(filename) as f:
         return f.read() == "0\n"
 
@@ -70,8 +72,10 @@ def disk_name_for_partition(partition):
     :return:
     """
     name = os.path.basename(partition["device"])
+
     if name.startswith("/dev/mmcblk"):
-        return re.sub("p[0-9]+$", "", name)    
+        return re.sub("p[0-9]+$", "", name)
+
     return re.sub("[0-9]+$", "", name)
 
 
@@ -83,9 +87,7 @@ class FstabGenerator(object):
     :param mount_options:
     :param ssd_extra_mount_options:
     """
-
-    def __init__(self, partitions, root_mount_point, mount_options,
-                 ssd_extra_mount_options):
+    def __init__(self, partitions, root_mount_point, mount_options, ssd_extra_mount_options):
         self.partitions = partitions
         self.root_mount_point = root_mount_point
         self.mount_options = mount_options
@@ -101,6 +103,7 @@ class FstabGenerator(object):
         self.find_ssd_disks()
         self.generate_fstab()
         self.create_mount_points()
+
         return None
 
     def find_ssd_disks(self):
@@ -112,22 +115,24 @@ class FstabGenerator(object):
         """ Create fstab. """
         mkdir_p(os.path.join(self.root_mount_point, "etc"))
         fstab_path = os.path.join(self.root_mount_point, "etc", "fstab")
+
         with open(fstab_path, "w") as fl:
             print(HEADER, file=fl)
+
             for partition in self.partitions:
                 dct = self.generate_fstab_line_info(partition)
+
                 if dct:
                     self.print_fstab_line(dct, file=fl)
 
             if self.root_is_ssd:
                 # Mount /tmp on a tmpfs
-                dct = dict(
-                    device="tmpfs",
-                    mount_point="/tmp",
-                    fs="tmpfs",
-                    options="defaults,noatime,mode=1777",
-                    check=0,
-                )
+                dct = dict(device="tmpfs",
+                           mount_point="/tmp",
+                           fs="tmpfs",
+                           options="defaults,noatime,mode=1777",
+                           check=0,
+                           )
                 self.print_fstab_line(dct, file=fl)
 
     def generate_fstab_line_info(self, partition):
@@ -140,7 +145,6 @@ class FstabGenerator(object):
         mount_point = partition["mountPoint"]
         disk_name = disk_name_for_partition(partition)
         is_ssd = disk_name in self.ssd_disks
-
         fs = FS_MAP.get(fs, fs)
 
         if not mount_point and not fs == "swap":
@@ -149,6 +153,7 @@ class FstabGenerator(object):
         options = self.mount_options.get(fs, self.mount_options["default"])
         if is_ssd:
             extra = self.ssd_extra_mount_options.get(fs)
+
             if extra:
                 options += "," + extra
 
@@ -162,12 +167,12 @@ class FstabGenerator(object):
         if mount_point == "/":
             self.root_is_ssd = is_ssd
 
-        return dict(
-            device="UUID=" + partition["uuid"],
-            mount_point=mount_point or "swap",
-            fs=fs,
-            options=options,
-            check=check)
+        return dict(device="UUID=" + partition["uuid"],
+                    mount_point=mount_point or "swap",
+                    fs=fs,
+                    options=options,
+                    check=check,
+                    )
 
     def print_fstab_line(self, dct, file=None):
         """ Prints line to '/etc/fstab' file.
@@ -175,12 +180,12 @@ class FstabGenerator(object):
         :param dct:
         :param file:
         """
-        line = "{:41} {:<14} {:<7} {:<10} 0       {}".format(
-            dct["device"],
-            dct["mount_point"],
-            dct["fs"],
-            dct["options"],
-            dct["check"])
+        line = "{:41} {:<14} {:<7} {:<10} 0       {}".format(dct["device"],
+                                                             dct["mount_point"],
+                                                             dct["fs"],
+                                                             dct["options"],
+                                                             dct["check"],
+                                                             )
         print(line, file=file)
 
     def create_mount_points(self):
@@ -199,10 +204,8 @@ def run():
     conf = libcalamares.job.configuration
     partitions = gs.value("partitions")
     root_mount_point = gs.value("rootMountPoint")
-
     mount_options = conf["mountOptions"]
     ssd_extra_mount_options = conf.get("ssdExtraMountOptions", {})
+    generator = FstabGenerator(partitions, root_mount_point, mount_options, ssd_extra_mount_options)
 
-    generator = FstabGenerator(partitions, root_mount_point,
-                               mount_options, ssd_extra_mount_options)
     return generator.run()
diff --git a/src/modules/grubcfg/main.py b/src/modules/grubcfg/main.py
index e7d147caf..e8c3413fc 100644
--- a/src/modules/grubcfg/main.py
+++ b/src/modules/grubcfg/main.py
@@ -49,8 +49,10 @@ def modify_grub_default(partitions, root_mount_point, distributor):
             swap_uuid = partition["uuid"]
 
     kernel_params = ["quiet"]
+
     if use_splash:
         kernel_params.append(use_splash)
+
     if swap_uuid:
         kernel_params.append("resume=UUID={!s}".format(swap_uuid))
 
@@ -89,6 +91,7 @@ def modify_grub_default(partitions, root_mount_point, distributor):
 
                 for existing_param in existing_params:
                     existing_param_name = existing_param.split("=")[0]
+
                     if existing_param_name not in ["quiet", "resume", "splash"]:  # the only ones we ever add
                         kernel_params.append(existing_param)
 
@@ -100,6 +103,7 @@ def modify_grub_default(partitions, root_mount_point, distributor):
                 have_distributor_line = True
     else:
         lines = []
+
         if "defaults" in libcalamares.job.configuration:
             for key, value in libcalamares.job.configuration["defaults"].items():
                 if value.__class__.__name__ == "bool":
@@ -109,6 +113,7 @@ def modify_grub_default(partitions, root_mount_point, distributor):
                         escaped_value = "false"
                 else:
                     escaped_value = str(value).replace("'", "'\\''")
+
                 lines.append("{!s}=\"{!s}\"".format(key, escaped_value))
 
     if not have_kernel_cmd:
@@ -133,4 +138,5 @@ def run():
     root_mount_point = libcalamares.globalstorage.value("rootMountPoint")
     branding = libcalamares.globalstorage.value("branding")
     distributor = branding["bootloaderEntryName"]
+
     return modify_grub_default(partitions, root_mount_point, distributor)
diff --git a/src/modules/hwclock/main.py b/src/modules/hwclock/main.py
index 4bc672713..54dea7451 100644
--- a/src/modules/hwclock/main.py
+++ b/src/modules/hwclock/main.py
@@ -32,8 +32,7 @@ def run():
     try:
         subprocess.check_call(["hwclock", "--systohc", "--utc"])
     except subprocess.CalledProcessError as e:
-        return "Cannot set hardware clock.", \
-               "hwclock terminated with exit code {}.".format(e.returncode)
+        return "Cannot set hardware clock.", "hwclock terminated with exit code {}.".format(e.returncode)
 
     shutil.copy2("/etc/adjtime", "{!s}/etc/".format(root_mount_point))
 
diff --git a/src/modules/initcpio/main.py b/src/modules/initcpio/main.py
index fdf163a64..f7c1cd336 100644
--- a/src/modules/initcpio/main.py
+++ b/src/modules/initcpio/main.py
@@ -34,4 +34,5 @@ def run():
     :return:
     """
     run_mkinitcpio()
+
     return None
diff --git a/src/modules/initcpiocfg/main.py b/src/modules/initcpiocfg/main.py
index f3754f696..f811e8edb 100644
--- a/src/modules/initcpiocfg/main.py
+++ b/src/modules/initcpiocfg/main.py
@@ -31,15 +31,16 @@ def cpuinfo():
     cpu_info['proc0']={...}
     cpu_info['proc1']={...}
     """
-    cpuinfo = OrderedDict()
+    cpu_info = OrderedDict()
     procinfo = OrderedDict()
 
     nprocs = 0
+
     with open('/proc/cpuinfo') as f:
         for line in f:
             if not line.strip():
                 # end of one processor
-                cpuinfo["proc{!s}".format(nprocs)] = procinfo
+                cpu_info["proc{!s}".format(nprocs)] = procinfo
                 nprocs += 1
                 # Reset
                 procinfo = OrderedDict()
@@ -49,7 +50,7 @@ def cpuinfo():
                 else:
                     procinfo[line.split(':')[0].strip()] = ''
 
-    return cpuinfo
+    return cpu_info
 
 
 def set_mkinitcpio_hooks_and_modules(hooks, modules, root_mount_point):
@@ -71,6 +72,7 @@ def set_mkinitcpio_hooks_and_modules(hooks, modules, root_mount_point):
             mklins[i] = "MODULES=\"{!s}\"".format(joined_modules)
 
     path = os.path.join(root_mount_point, "etc/mkinitcpio.conf")
+
     with open(path, "w") as mkinitcpio_file:
         mkinitcpio_file.write("\n".join(mklins) + "\n")
 
@@ -95,6 +97,7 @@ def modify_mkinitcpio_conf(partitions, root_mount_point):
     for partition in partitions:
         if partition["fs"] == "linuxswap":
             swap_uuid = partition["uuid"]
+
         if partition["fs"] == "btrfs":
             btrfs = "yes"
 
@@ -121,4 +124,5 @@ def run():
     partitions = libcalamares.globalstorage.value("partitions")
     root_mount_point = libcalamares.globalstorage.value("rootMountPoint")
     modify_mkinitcpio_conf(partitions, root_mount_point)
+
     return None
diff --git a/src/modules/initramfs/main.py b/src/modules/initramfs/main.py
index 73faa1f9b..37279c4d3 100644
--- a/src/modules/initramfs/main.py
+++ b/src/modules/initramfs/main.py
@@ -26,6 +26,7 @@ def run():
 
     :return:
     """
-    returnCode = chroot_call(["update-initramfs", "-k", "all", "-u"])
-    if returnCode != 0:
-        return ("Failed to run update-initramfs on the target", "The exit code was {}".format(returnCode))
+    return_code = chroot_call(["update-initramfs", "-k", "all", "-u"])
+
+    if return_code != 0:
+        return "Failed to run update-initramfs on the target", "The exit code was {}".format(return_code)
diff --git a/src/modules/localecfg/main.py b/src/modules/localecfg/main.py
index ae477fec0..8f6330fe3 100644
--- a/src/modules/localecfg/main.py
+++ b/src/modules/localecfg/main.py
@@ -27,9 +27,9 @@ import libcalamares
 
 def run():
     """ Create locale """
-
     us = '#en_US'
     locale = libcalamares.globalstorage.value("lcLocale")
+
     if not locale:
         locale = 'en_US.UTF-8 UTF-8'
 
@@ -43,6 +43,7 @@ def run():
     # run locale-gen if detected
     if os.path.exists('/etc/locale.gen'):
         text = []
+
         with open("{!s}/etc/locale.gen".format(install_path), "r") as gen:
             text = gen.readlines()
 
@@ -52,15 +53,18 @@ def run():
                 if us in line and line[0] == "#":
                     # uncomment line
                     line = line[1:]
+
                 if locale in line and line[0] == "#":
                     # uncomment line
                     line = line[1:]
+
                 gen.write(line)
 
         libcalamares.utils.chroot_call(['locale-gen'])
         print('locale.gen done')
 
     locale_conf_path = os.path.join(install_path, "etc/locale.conf")
+
     with open(locale_conf_path, "w") as locale_conf:
         locale_split = locale.split(' ')[0]
         locale_conf.write("LANG={!s}\n".format(locale_split))
diff --git a/src/modules/machineid/main.py b/src/modules/machineid/main.py
index 5bd807428..ddf134f5a 100644
--- a/src/modules/machineid/main.py
+++ b/src/modules/machineid/main.py
@@ -33,16 +33,22 @@ def run():
     enable_dbus = libcalamares.job.configuration["dbus"]
     enable_symlink = libcalamares.job.configuration["symlink"]
     target_systemd_machineid_file = "{}/etc/machine-id".format(root_mount_point)
+
     if enable_systemd:
         if os.path.exists(target_systemd_machineid_file):
             os.remove(target_systemd_machineid_file)
+
         check_chroot_call("systemd-machine-id-setup")
+
     if enable_dbus:
         target_dbus_machineid_file = "{}/var/lib/dbus/machine-id".format(root_mount_point)
+
         if os.path.exists(target_dbus_machineid_file):
             os.remove(target_dbus_machineid_file)
+
         if enable_symlink and os.path.exists(target_systemd_machineid_file):
             check_chroot_call(["ln", "-s", "/etc/machine-id", "/var/lib/dbus/machine-id"])
         else:
             check_chroot_call(["dbus-uuidgen", "--ensure"])
+
     return None
diff --git a/src/modules/mount/main.py b/src/modules/mount/main.py
index 5d17b8ba0..f5b0e09e9 100644
--- a/src/modules/mount/main.py
+++ b/src/modules/mount/main.py
@@ -35,17 +35,16 @@ def mount_partitions(root_mount_point, partitions):
         # Create mount point with `+` rather than `os.path.join()` because
         # `partition["mountPoint"]` starts with a '/'.
         mount_point = root_mount_point + partition["mountPoint"]
-
         fstype = partition.get("fs", "")
+
         if fstype == "fat16" or fstype == "fat32":
             fstype = "vfat"
 
-        libcalamares.utils.mount(
-            partition["device"],
-            mount_point,
-            fstype,
-            partition.get("options", "")
-        )
+        libcalamares.utils.mount(partition["device"],
+                                 mount_point,
+                                 fstype,
+                                 partition.get("options", ""),
+                                 )
 
 
 def run():
@@ -61,14 +60,14 @@ def run():
     # Sort by mount points to ensure / is mounted before the rest
     partitions.sort(key=lambda x: x["mountPoint"])
     mount_partitions(root_mount_point, partitions)
-
     mount_partitions(root_mount_point, extra_mounts)
-
     fw_type = libcalamares.globalstorage.value("firmwareType")
+
     if fw_type == 'efi':
         mount_partitions(root_mount_point, extra_mounts_efi)
 
     libcalamares.globalstorage.insert("rootMountPoint", root_mount_point)
+
     # Remember the extra mounts for the unpackfs module
     if fw_type == 'efi':
         libcalamares.globalstorage.insert("extraMounts", extra_mounts + extra_mounts_efi)
diff --git a/src/modules/networkcfg/main.py b/src/modules/networkcfg/main.py
index 4a558b946..b9c347d45 100644
--- a/src/modules/networkcfg/main.py
+++ b/src/modules/networkcfg/main.py
@@ -30,8 +30,7 @@ def run():
 
     root_mount_point = libcalamares.globalstorage.value("rootMountPoint")
     source_nm = "/etc/NetworkManager/system-connections/"
-    target_nm = os.path.join(root_mount_point,
-                             "etc/NetworkManager/system-connections/")
+    target_nm = os.path.join(root_mount_point, "etc/NetworkManager/system-connections/")
 
     # Sanity checks.  We don't want to do anything if a network
     # configuration already exists on the target
@@ -50,8 +49,7 @@ def run():
             try:
                 shutil.copy(source_network, target_network)
             except FileNotFoundError:
-                libcalamares.utils.debug(
-                    "Can't copy network configuration files in {}".format(source_network))
+                libcalamares.utils.debug("Can't copy network configuration files in {}".format(source_network))
             except FileExistsError:
                 pass
 
diff --git a/src/modules/packages/main.py b/src/modules/packages/main.py
index 72ab693b5..8149d1eb9 100644
--- a/src/modules/packages/main.py
+++ b/src/modules/packages/main.py
@@ -34,26 +34,29 @@ class PackageManager:
         """ Installs packages.
 
         :param pkgs:
+        :param from_local:
         """
         if self.backend == "packagekit":
             for pkg in pkgs:
                 check_chroot_call(["pkcon", "-py", "install", pkg])
         elif self.backend == "zypp":
-            check_chroot_call(
-                ["zypper", "--non-interactive", "--quiet-install", "install",
-                 "--auto-agree-with-licenses", "install"] + pkgs)
+            check_chroot_call(["zypper", "--non-interactive", "--quiet-install", "install",
+                               "--auto-agree-with-licenses", "install"] + pkgs)
         elif self.backend == "yum":
             check_chroot_call(["yum", "install", "-y"] + pkgs)
         elif self.backend == "dnf":
             check_chroot_call(["dnf", "install", "-y"] + pkgs)
         elif self.backend == "urpmi":
-            check_chroot_call(
-                ["urpmi", "--download-all", "--no-suggests", "--no-verify-rpm",
-                 "--fastunsafe", "--ignoresize", "--nolock", "--auto"] + pkgs)
+            check_chroot_call(["urpmi", "--download-all", "--no-suggests", "--no-verify-rpm",
+                               "--fastunsafe", "--ignoresize", "--nolock", "--auto"] + pkgs)
         elif self.backend == "apt":
             check_chroot_call(["apt-get", "-q", "-y", "install"] + pkgs)
         elif self.backend == "pacman":
-            pacman_flags = "-U" if from_local else "-Sy"
+            if from_local:
+                pacman_flags = "-U"
+            else:
+                pacman_flags = "-Sy"
+
             check_chroot_call(["pacman", pacman_flags, "--noconfirm"] + pkgs)
         elif self.backend == "portage":
             check_chroot_call(["emerge", "-v"] + pkgs)
@@ -110,17 +113,19 @@ def run():
     :return:
     """
     backend = libcalamares.job.configuration.get("backend")
+
     if backend not in ("packagekit", "zypp", "yum", "dnf", "urpmi", "apt", "pacman", "portage", "entropy"):
-        return ("Bad backend", "backend=\"{}\"".format(backend))
+        return "Bad backend", "backend=\"{}\"".format(backend)
 
     pkgman = PackageManager(backend)
-
     operations = libcalamares.job.configuration.get("operations", [])
+
     for entry in operations:
         run_operations(pkgman, entry)
 
     if libcalamares.globalstorage.contains("packageOperations"):
         operations = libcalamares.globalstorage.value("packageOperations")
+
         for entry in operations:
             run_operations(pkgman, entry)
 
diff --git a/src/modules/removeuser/main.py b/src/modules/removeuser/main.py
index 51150a9a2..05366caf0 100644
--- a/src/modules/removeuser/main.py
+++ b/src/modules/removeuser/main.py
@@ -24,12 +24,11 @@ import libcalamares
 
 def run():
     """ Remove live user from target system """
+    username = libcalamares.job.configuration["username"]
 
-    username = libcalamares.job.configuration[("username")]
     try:
         libcalamares.utils.check_chroot_call(["userdel", "-f", "-r", username])
     except subprocess.CalledProcessError as e:
-        libcalamares.utils.debug( "Cannot remove user. " +
-                                  "userdel terminated with exit code {}.".format(e.returncode))
+        libcalamares.utils.debug("Cannot remove user.", "'userdel' terminated with exit code {}.".format(e.returncode))
 
     return None
diff --git a/src/modules/services/main.py b/src/modules/services/main.py
index 941ea51e1..b96ae7708 100644
--- a/src/modules/services/main.py
+++ b/src/modules/services/main.py
@@ -24,38 +24,31 @@ import libcalamares
 
 def run():
     """ Setup systemd services """
-
     services = libcalamares.job.configuration['services']
     targets = libcalamares.job.configuration['targets']
 
     # enable services
     for svc in services:
-        ec = libcalamares.utils.chroot_call(['systemctl',
-                                             'enable',
-                                             '{}.service'.format(svc['name'])])
+        ec = libcalamares.utils.chroot_call(['systemctl', 'enable', '{}.service'.format(svc['name'])])
+
         if ec != 0:
             if svc['mandatory']:
                 return "Cannot enable systemd service {}".format(svc['name']), \
                        "systemctl enable call in chroot returned error code {}".format(ec)
             else:
-                libcalamares.utils.debug(
-                    "Cannot enable systemd service {}".format(svc['name']))
-                libcalamares.utils.debug(
-                    "systemctl enable call in chroot returned error code {}".format(ec))
+                libcalamares.utils.debug("Cannot enable systemd service {}".format(svc['name']))
+                libcalamares.utils.debug("systemctl enable call in chroot returned error code {}".format(ec))
 
     # enable targets
     for tgt in targets:
-        ec = libcalamares.utils.chroot_call(['systemctl',
-                                             'enable',
-                                             '{}.target'.format(tgt['name'])])
+        ec = libcalamares.utils.chroot_call(['systemctl', 'enable', '{}.target'.format(tgt['name'])])
+
         if ec != 0:
             if tgt['mandatory']:
                 return "Cannot enable systemd target {}".format(tgt['name']), \
                        "systemctl enable call in chroot returned error code {}".format(ec)
             else:
-                libcalamares.utils.debug(
-                    "Cannot enable systemd target {}".format(tgt['name']))
-                libcalamares.utils.debug(
-                    "systemctl enable call in chroot returned error code {}".format(ec))
+                libcalamares.utils.debug("Cannot enable systemd target {}".format(tgt['name']))
+                libcalamares.utils.debug("systemctl enable call in chroot returned error code {}".format(ec))
 
     return None
diff --git a/src/modules/umount/main.py b/src/modules/umount/main.py
index 479cfc702..d0e18dfbf 100644
--- a/src/modules/umount/main.py
+++ b/src/modules/umount/main.py
@@ -31,10 +31,13 @@ def list_mounts(root_mount_point):
     :return:
     """
     lst = []
+
     for line in open("/etc/mtab").readlines():
         device, mount_point, _ = line.split(" ", 2)
+
         if mount_point.startswith(root_mount_point):
             lst.append((device, mount_point))
+
     return lst
 
 
@@ -44,10 +47,12 @@ def run():
     :return:
     """
     root_mount_point = libcalamares.globalstorage.value("rootMountPoint")
+
     if not root_mount_point:
         return ("No mount point for root partition in globalstorage",
                 "globalstorage does not contain a \"rootMountPoint\" key, "
                 "doing nothing")
+
     if not os.path.exists(root_mount_point):
         return ("Bad mount point for root partition in globalstorage",
                 "globalstorage[\"rootMountPoint\"] is \"{}\", which does not "
@@ -62,4 +67,5 @@ def run():
         subprocess.check_call(["umount", "-lv", mount_point])
 
     os.rmdir(root_mount_point)
+
     return None
diff --git a/src/modules/unpackfs/main.py b/src/modules/unpackfs/main.py
index 1dac7b62f..2fbcfbee8 100644
--- a/src/modules/unpackfs/main.py
+++ b/src/modules/unpackfs/main.py
@@ -26,7 +26,6 @@ import shutil
 import subprocess
 import sys
 import tempfile
-from collections import namedtuple
 
 from libcalamares import *
 
@@ -59,10 +58,13 @@ def list_excludes(destination):
     """
     lst = []
     extra_mounts = globalstorage.value("extraMounts")
+
     for extra_mount in extra_mounts:
         mount_point = extra_mount["mountPoint"]
+
         if mount_point:
             lst.extend(['--exclude', mount_point + '/'])
+
     return lst
 
 
@@ -87,11 +89,7 @@ def file_copy(source, dest, progress_cb):
     args = ['rsync', '-aHAXr']
     args.extend(list_excludes(dest))
     args.extend(['--progress', source, dest])
-    process = subprocess.Popen(args,
-                               env=at_env,
-                               bufsize=1,
-                               stdout=subprocess.PIPE,
-                               close_fds=ON_POSIX)
+    process = subprocess.Popen(args, env=at_env, bufsize=1, stdout=subprocess.PIPE, close_fds=ON_POSIX)
 
     for line in iter(process.stdout.readline, b''):
         # small comment on this regexp.
@@ -107,6 +105,7 @@ def file_copy(source, dest, progress_cb):
         # therefore we can easily subtract x from y in order to get real files
         # copied / processed count.
         m = re.findall(r'xfr#(\d+), ir-chk=(\d+)/(\d+)', line.decode())
+
         if m:
             # we've got a percentage update
             num_files_remaining = int(m[0][1])
@@ -117,9 +116,12 @@ def file_copy(source, dest, progress_cb):
             # I guess we're updating every 100 files...
             if num_files_copied % 100 == 0:
                 progress_cb(num_files_copied)
+
     process.wait()
+
     if process.returncode != 0:
         return "rsync failed with error code {}.".format(process.returncode)
+
     return None
 
 
@@ -128,6 +130,7 @@ class UnpackOperation:
 
     :param entries:
     """
+
     def __init__(self, entries):
         self.entries = entries
         self.entry_for_source = dict((x.source, x) for x in self.entries)
@@ -135,6 +138,7 @@ class UnpackOperation:
     def report_progress(self):
         """ Pass progress to user interface """
         progress = float(0)
+
         for entry in self.entries:
             if entry.total == 0:
                 continue
@@ -152,10 +156,10 @@ class UnpackOperation:
         :return:
         """
         source_mount_path = tempfile.mkdtemp()
+
         try:
             for entry in self.entries:
-                imgbasename = os.path.splitext(
-                    os.path.basename(entry.source))[0]
+                imgbasename = os.path.splitext(os.path.basename(entry.source))[0]
                 imgmountdir = os.path.join(source_mount_path, imgbasename)
                 os.mkdir(imgmountdir)
 
@@ -169,20 +173,19 @@ class UnpackOperation:
                                 "Failed to find unsquashfs, make sure you have "
                                 "the squashfs-tools package installed")
 
-                    fslist = subprocess.check_output(["unsquashfs",
-                                                      "-l",
-                                                      entry.source])
+                    fslist = subprocess.check_output(["unsquashfs", "-l", entry.source])
+
                 if entry.sourcefs == "ext4":
-                    fslist = subprocess.check_output(["find",
-                                                      imgmountdir,
-                                                      "-type", "f"])
+                    fslist = subprocess.check_output(["find", imgmountdir, "-type", "f"])
+
                 entry.total = len(fslist.splitlines())
 
                 self.report_progress()
                 error_msg = self.unpack_image(entry, imgmountdir)
+
                 if error_msg:
-                    return ("Failed to unpack image {}".format(entry.source),
-                            error_msg)
+                    return "Failed to unpack image {}".format(entry.source), error_msg
+
             return None
         finally:
             shutil.rmtree(source_mount_path)
@@ -193,12 +196,7 @@ class UnpackOperation:
         :param entry:
         :param imgmountdir:
         """
-        subprocess.check_call(["mount",
-                               entry.source,
-                               imgmountdir,
-                               "-t",
-                               entry.sourcefs,
-                               "-o", "loop"])
+        subprocess.check_call(["mount", entry.source, imgmountdir, "-t", entry.sourcefs, "-o", "loop"])
 
     def unpack_image(self, entry, imgmountdir):
         """ Unpacks image.
@@ -207,7 +205,6 @@ class UnpackOperation:
         :param imgmountdir:
         :return:
         """
-
         def progress_cb(copied):
             """ Copies file to given destination target.
 
@@ -217,9 +214,7 @@ class UnpackOperation:
             self.report_progress()
 
         try:
-            return file_copy(imgmountdir,
-                             entry.destination,
-                             progress_cb)
+            return file_copy(imgmountdir, entry.destination, progress_cb)
         finally:
             subprocess.check_call(["umount", "-l", imgmountdir])
 
@@ -245,14 +240,17 @@ def run():
     PATH_PROCFS = '/proc/filesystems'
 
     root_mount_point = globalstorage.value("rootMountPoint")
+
     if not root_mount_point:
         return ("No mount point for root partition in globalstorage",
                 "globalstorage does not contain a \"rootMountPoint\" key, "
                 "doing nothing")
+
     if not os.path.exists(root_mount_point):
         return ("Bad mount point for root partition in globalstorage",
                 "globalstorage[\"rootMountPoint\"] is \"{}\", which does not "
                 "exist, doing nothing".format(root_mount_point))
+
     unpack = list()
 
     for entry in job.configuration["unpack"]:
@@ -279,12 +277,13 @@ def run():
         destination = os.path.abspath(root_mount_point + entry["destination"])
 
         if not os.path.exists(source) or os.path.isdir(source):
-            return ("Bad source", "source=\"{}\"".format(source))
+            return "Bad source", "source=\"{}\"".format(source)
+
         if not os.path.isdir(destination):
-            return ("Bad destination",
-                    "destination=\"{}\"".format(destination))
+            return "Bad destination", "destination=\"{}\"".format(destination)
 
         unpack.append(UnpackEntry(source, sourcefs, destination))
 
     unpackop = UnpackOperation(unpack)
+
     return unpackop.run()