diff --git a/telethon/client/chats.py b/telethon/client/chats.py
index ee2aa56b..02188e73 100644
--- a/telethon/client/chats.py
+++ b/telethon/client/chats.py
@@ -138,7 +138,6 @@ class ChatMethods(UserMethods):
                                 return
 
         elif isinstance(entity, types.InputPeerChat):
-            # TODO We *could* apply the `filter` here ourselves
             full = await self(
                 functions.messages.GetFullChatRequest(entity.chat_id))
             if not isinstance(
diff --git a/telethon/client/dialogs.py b/telethon/client/dialogs.py
index c7b9c6d7..1adb9ba2 100644
--- a/telethon/client/dialogs.py
+++ b/telethon/client/dialogs.py
@@ -111,7 +111,7 @@ class DialogMethods(UserMethods):
         return dialogs
 
     @async_generator
-    async def iter_drafts(self):  # TODO: Ability to provide a `filter`
+    async def iter_drafts(self):
         """
         Iterator over all open draft messages.
 
diff --git a/telethon/client/telegrambaseclient.py b/telethon/client/telegrambaseclient.py
index 7bc73b5c..0d0f3c88 100644
--- a/telethon/client/telegrambaseclient.py
+++ b/telethon/client/telegrambaseclient.py
@@ -219,13 +219,6 @@ class TelegramBaseClient(abc.ABC):
         self._last_ping = datetime.now()
         self._ping_delay = timedelta(minutes=1)
 
-        # Also have another delay for GetStateRequest.
-        #
-        # If the connection is kept alive for long without invoking any
-        # high level request the server simply stops sending updates.
-        # TODO maybe we can have ._last_request instead if any req works?
-        self._last_state = datetime.now()
-        self._state_delay = timedelta(hours=1)
         self._state = None
         self._updates_handle = None
         self._last_request = time.time()
@@ -295,8 +288,6 @@ class TelegramBaseClient(abc.ABC):
         Disconnects from Telegram.
         """
         await self._sender.disconnect()
-        # TODO What to do with the update state? Does it belong here?
-        # self.session.set_update_state(0, self.updates.get_update_state(0))
         self.session.close()
 
     async def _switch_dc(self, new_dc):
diff --git a/telethon/network/mtprotosender.py b/telethon/network/mtprotosender.py
index a6b503b8..0a92063e 100644
--- a/telethon/network/mtprotosender.py
+++ b/telethon/network/mtprotosender.py
@@ -25,11 +25,6 @@ __log__ = logging.getLogger(__name__)
 _reconnect_sentinel = object()
 
 
-# TODO Create some kind of "ReconnectionPolicy" that allows specifying
-# what should be done in case of some errors, with some sane defaults.
-# For instance, should all messages be set with an error upon network
-# loss? Should we try reconnecting forever? A certain amount of times?
-# A timeout? What about recoverable errors, like connection reset?
 class MTProtoSender:
     """
     MTProto Mobile Protocol sender
@@ -386,10 +381,6 @@ class MTProtoSender:
         Besides `connect`, only this method ever receives data.
         """
         while self._user_connected and not self._reconnecting:
-            # TODO Are there more exceptions besides timeout?
-            # Disconnecting or switching off WiFi only resulted in
-            # timeouts, and once the network was back it continued
-            # on its own after a short delay.
             try:
                 __log__.debug('Receiving items from the network...')
                 body = await self._connection.recv()
diff --git a/telethon/tl/core/gzippacked.py b/telethon/tl/core/gzippacked.py
index 7b146363..4683ed6e 100644
--- a/telethon/tl/core/gzippacked.py
+++ b/telethon/tl/core/gzippacked.py
@@ -20,7 +20,6 @@ class GzipPacked(TLObject):
            Note that this only applies to content related requests.
         """
         data = bytes(request)
-        # TODO This threshold could be configurable
         if isinstance(request, TLRequest) and len(data) > 512:
             gzipped = bytes(GzipPacked(data))
             return gzipped if len(gzipped) < len(data) else data
@@ -28,7 +27,6 @@ class GzipPacked(TLObject):
             return data
 
     def __bytes__(self):
-        # TODO Maybe compress level could be an option
         return struct.pack('<I', GzipPacked.CONSTRUCTOR_ID) + \
                TLObject.serialize_bytes(gzip.compress(self.data))
 
diff --git a/telethon/update_state.py b/telethon/update_state.py
index 72e8024d..da7c0f9e 100644
--- a/telethon/update_state.py
+++ b/telethon/update_state.py
@@ -73,7 +73,6 @@ class UpdateState:
             for u in update.updates:
                 u._entities = entities
                 self._updates.put(u)
-        # TODO Handle "tl.UpdatesTooLong"
         else:
             update._entities = {}
             self._updates.put(update)
diff --git a/telethon_generator/generators/docs.py b/telethon_generator/generators/docs.py
index 21b0e244..9ccfc19c 100755
--- a/telethon_generator/generators/docs.py
+++ b/telethon_generator/generators/docs.py
@@ -80,7 +80,6 @@ def _find_title(html_file):
 def _build_menu(docs, filename, root, relative_main_index):
     """Builds the menu using the given DocumentWriter up to 'filename',
        which must be a file (it cannot be a directory)"""
-    # TODO Maybe this could be part of DocsWriter itself, "build path menu"
     filename = _get_relative_path(filename, root)
     docs.add_menu('API', relative_main_index)
 
@@ -238,7 +237,6 @@ def _write_html_pages(tlobjects, errors, layer, input_res, output_dir):
     # Save 'Type: [Constructors]' for use in both:
     # * Seeing the return type or constructors belonging to the same type.
     # * Generating the types documentation, showing available constructors.
-    # TODO Tried using 'defaultdict(list)' with strange results, make it work.
     original_paths = {
         'css': 'css',
         'arrow': 'img/arrow.svg',
@@ -254,14 +252,11 @@ def _write_html_pages(tlobjects, errors, layer, input_res, output_dir):
                       for k, v in original_paths.items()}
 
     original_paths['default_css'] = 'light'  # docs.<name>.css, local path
-    type_to_constructors = {}
-    type_to_functions = {}
+    type_to_constructors = defaultdict(list)
+    type_to_functions = defaultdict(list)
     for tlobject in tlobjects:
         d = type_to_functions if tlobject.is_function else type_to_constructors
-        if tlobject.result in d:
-            d[tlobject.result].append(tlobject)
-        else:
-            d[tlobject.result] = [tlobject]
+        d[tlobject.result].append(tlobject)
 
     for t, cs in type_to_constructors.items():
         type_to_constructors[t] = list(sorted(cs, key=lambda c: c.name))
@@ -412,7 +407,6 @@ def _write_html_pages(tlobjects, errors, layer, input_res, output_dir):
                     docs.write_text('You can import these from '
                                     '<code>telethon.errors</code>.')
 
-            # TODO Bit hacky, make everything like this? (prepending '../')
             depth = '../' * (2 if tlobject.namespace else 1)
             docs.add_script(src='prependPath = "{}";'.format(depth))
             docs.add_script(relative_src=paths['search.js'])