diff --git a/actions/i2p b/actions/i2p
index c170aadf0..2ee857510 100755
--- a/actions/i2p
+++ b/actions/i2p
@@ -43,7 +43,8 @@ def parse_arguments():
         'add-favorite', help='Add an eepsite to the list of favorites')
     subparser.add_argument('--name', help='Name of the entry', required=True)
     subparser.add_argument('--url', help='URL of the entry', required=True)
-    subparser.add_argument('--description', help='short description', required=False)
+    subparser.add_argument('--description', help='Short description',
+                           required=False)
     subparser.add_argument('--icon', help='URL to icon', required=False)
 
     subparser = subparsers.add_parser('set-tunnel-property',
@@ -92,12 +93,8 @@ def subcommand_add_favorite(arguments):
     url = arguments.url
 
     editor = RouterEditor()
-    editor.read_conf().add_favorite(
-        arguments.name,
-        url,
-        arguments.description,
-        arguments.icon
-    ).write_conf()
+    editor.read_conf().add_favorite(arguments.name, url, arguments.description,
+                                    arguments.icon).write_conf()
 
     print('Added {} to favorites'.format(url))
 
diff --git a/plinth/modules/i2p/__init__.py b/plinth/modules/i2p/__init__.py
index 8cfc59e58..a0334e14b 100644
--- a/plinth/modules/i2p/__init__.py
+++ b/plinth/modules/i2p/__init__.py
@@ -25,6 +25,7 @@ from plinth import service as service_module
 from plinth.menu import main_menu
 from plinth.modules.i2p.resources import FAVORITES
 from plinth.modules.users import register_group
+
 from .manifest import backup, clients
 
 version = 1
@@ -97,8 +98,10 @@ def setup(helper, old_version=None):
     for fav in FAVORITES:
         args = [
             'add-favorite',
-            '--name', fav.get('name'),
-            '--url', fav.get('url'),
+            '--name',
+            fav.get('name'),
+            '--url',
+            fav.get('url'),
         ]
         if 'icon' in fav:
             args.extend(['--icon', fav.get('icon')])
diff --git a/plinth/modules/i2p/helpers.py b/plinth/modules/i2p/helpers.py
index 883db10b8..6374fc9f2 100644
--- a/plinth/modules/i2p/helpers.py
+++ b/plinth/modules/i2p/helpers.py
@@ -17,9 +17,9 @@
 Various helpers for the I2P app.
 """
 
-from collections import OrderedDict
 import os
 import re
+from collections import OrderedDict
 
 import augeas
 
@@ -137,10 +137,11 @@ class TunnelEditor():
         self.aug.set(self.calc_prop_path(tunnel_prop), value)
 
 
-class RouterEditor(object):
-    """
+class RouterEditor():
+    """Helper to edit I2P router configuration file using augeas.
 
     :type aug: augeas.Augeas
+
     """
 
     FAVORITE_PROP = 'routerconsole.favorites'
@@ -151,44 +152,58 @@ class RouterEditor(object):
         self.aug = None
 
     def read_conf(self):
-        self.aug = augeas.Augeas(flags=augeas.Augeas.NO_LOAD +
-                                       augeas.Augeas.NO_MODL_AUTOLOAD)
+        """Load an instance of Augeaus for processing APT configuration.
+
+        Chainable method.
+
+        """
+        self.aug = augeas.Augeas(
+            flags=augeas.Augeas.NO_LOAD + augeas.Augeas.NO_MODL_AUTOLOAD)
         self.aug.set('/augeas/load/Properties/lens', 'Properties.lns')
-        self.aug.set('/augeas/load/Properties/incl[last() + 1]', self.conf_filename)
+        self.aug.set('/augeas/load/Properties/incl[last() + 1]',
+                     self.conf_filename)
         self.aug.load()
         return self
 
     def write_conf(self):
+        """Write changes to the configuration file to disk.
+
+        Chainable method.
+
+        """
         self.aug.save()
         return self
 
     @property
     def favorite_property(self):
-        return '/files{filename}/{prop}'.format(filename=self.conf_filename, prop=self.FAVORITE_PROP)
+        """Return the favourites property from configuration file."""
+        return '/files{filename}/{prop}'.format(filename=self.conf_filename,
+                                                prop=self.FAVORITE_PROP)
 
     def add_favorite(self, name, url, description=None, icon=None):
-        """
-        Adds a favorite to the router.config
+        """Add a favorite to the router configuration file.
 
-        Favorites are in a single string and separated by ','.
-        none of the incoming params can therefore use commas.
-        I2P replaces the commas by dots.
+        Favorites are in a single string and separated by ','. none of the
+        incoming params can therefore use commas. I2P replaces the commas by
+        dots.
 
-        That's ok for the name and description,
-         but not for the url and icon
+        That's ok for the name and description, but not for the url and icon.
 
         :type name: basestring
         :type url: basestring
         :type description: basestring
         :type icon: basestring
+
         """
         if not description:
             description = ''
+
         if not icon:
             icon = '/themes/console/images/eepsite.png'
 
         if ',' in url:
             raise ValueError('URL cannot contain commas')
+
         if ',' in icon:
             raise ValueError('Icon cannot contain commas')
 
@@ -198,13 +213,12 @@ class RouterEditor(object):
         prop = self.favorite_property
         favorites = self.aug.get(prop) or ''
         new_favorite = '{name},{description},{url},{icon},'.format(
-            name=name, description=description, url=url,
-            icon=icon
-        )
+            name=name, description=description, url=url, icon=icon)
         self.aug.set(prop, favorites + new_favorite)
         return self
 
     def get_favorites(self):
+        """Return list of favorites."""
         favs_string = self.aug.get(self.favorite_property) or ''
         favs_split = favs_string.split(',')
 
@@ -218,15 +232,13 @@ class RouterEditor(object):
             raise SyntaxError("Invalid number of fields in favorite line")
 
         favs = OrderedDict()
-        i = 0
-        while i < favs_len:
-            next_idx = i + self.FAVORITE_TUPLE_SIZE
-            t = favs_split[i:next_idx]
-            name, description, url, icon = t
+        for index in range(0, favs_len, self.FAVORITE_TUPLE_SIZE):
+            next_index = index + self.FAVORITE_TUPLE_SIZE
+            name, description, url, icon = favs_split[index:next_index]
             favs[url] = {
-                "name": name,
-                "description": description,
-                "icon": icon
+                'name': name,
+                'description': description,
+                'icon': icon
             }
-            i = next_idx
+
         return favs
diff --git a/plinth/modules/i2p/manifest.py b/plinth/modules/i2p/manifest.py
index c65bdebe7..472b9e016 100644
--- a/plinth/modules/i2p/manifest.py
+++ b/plinth/modules/i2p/manifest.py
@@ -14,6 +14,9 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
+"""
+Application manifest for I2P.
+"""
 
 from django.utils.translation import ugettext_lazy as _
 
diff --git a/plinth/modules/i2p/resources.py b/plinth/modules/i2p/resources.py
index 1efe5783b..b6b9df7fd 100644
--- a/plinth/modules/i2p/resources.py
+++ b/plinth/modules/i2p/resources.py
@@ -14,6 +14,9 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
+"""
+Pre-defined list of favorites for I2P and some additional favorites.
+"""
 
 DEFAULT_FAVORITES = [
     {
diff --git a/plinth/modules/i2p/tests/__init__.py b/plinth/modules/i2p/tests/__init__.py
index 5d1e441e2..1bf534884 100644
--- a/plinth/modules/i2p/tests/__init__.py
+++ b/plinth/modules/i2p/tests/__init__.py
@@ -14,6 +14,10 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
+"""
+Common parts for all I2P tests.
+"""
+
 from pathlib import Path
 
 DATA_DIR = Path(__file__).parent / 'data'