Updated docstring in deleteMessage methods (#618)

* Removed "undocumented" notice

* Updated docstring according to Bot API documentation

* Removed extra line

telegram/bot.py

@@ -244,7 +244,13 @@ class Bot(TelegramObject):
     @log
     @message
     def delete_message(self, chat_id, message_id):
-        """Use this method to delete messages which were sent not later than 48 hours ago.
+        """Use this method to delete a message. A message can only be deleted if it was sent less
+        than 48 hours ago. Any such recently sent outgoing message may be deleted. Additionally,
+        if the bot is an administrator in a group chat, it can delete any message. If the bot is
+        an administrator in a supergroup, it can delete messages from any other user and service
+        messages about people joining or leaving the group (other types of service messages may
+        only be removed by the group creator). In channels, bots can only remove their own
+        messages.
 
         Args:
             chat_id (int|str): Unique identifier for the target chat or
@@ -252,10 +258,6 @@ class Bot(TelegramObject):
                 @channelusername).
             message_id (int): Unique message identifier.
 
-        Note:
-            This method is not documented, so it's not guaranteed to work. Also, its behaviour can
-            be changed at any time.
-
         Returns:
             bool: On success, `True` is returned.
 

telegram/message.py

@@ -551,10 +551,6 @@ class Message(TelegramObject):
             ...                   message_id=message.message_id,
             ...                   *args, **kwargs)
 
-        Note:
-            This method is not documented, so it's not guaranteed to work. Also, its behaviour can
-            be changed at any time.
-
         Returns:
             bool: On success, `True` is returned.
 

tests/test_bot.py

@@ -96,8 +96,6 @@ class BotTest(BaseTest, unittest.TestCase):
     @timeout(10)
     def test_deleteMessage_old_message(self):
         with self.assertRaisesRegexp(telegram.TelegramError, "can't be deleted"):
-            # NOTE: This behaviour can be changed in future because `deleteMessage` method is not
-            # documented in Bot API reference now.
             # Considering that the first message is old enough
             self._bot.delete_message(chat_id=self._chat_id, message_id=1)
 

tests/test_message.py

@@ -152,7 +152,6 @@ class MessageTest(BaseTest, unittest.TestCase):
             reply_to_message_id=1)
 
         with self.assertRaisesRegexp(telegram.TelegramError, "can't be deleted"):
-            # NOTE: This behaviour can be changed in future. See `tests/test_bot.py` for more info
             message.reply_to_message.delete()
 
     def test_equality(self):