diff --git a/telebot/__init__.py b/telebot/__init__.py
index df35dc7..39ba280 100644
--- a/telebot/__init__.py
+++ b/telebot/__init__.py
@@ -44,6 +44,11 @@ class TeleBot:
         self.commands = []
 
     def get_update(self):
+        """
+        Retrieves any updates from the Telegram API.
+        Registered listeners and applicable message handlers will be notified when a new message arrives.
+        :raises ApiException when a call has failed.
+        """
         updates = apihelper.get_updates(self.token, offset=(self.last_update_id + 1))
         new_messages = []
         for update in updates:
diff --git a/telebot/apihelper.py b/telebot/apihelper.py
index 4a85122..8fee253 100644
--- a/telebot/apihelper.py
+++ b/telebot/apihelper.py
@@ -7,16 +7,25 @@ from telebot import types
 
 
 def _make_request(token, method_name, method='get', params=None, files=None):
+    """
+    Makes a request to the Telegram API.
+    :param token: The bot's API token. (Created with @BotFather)
+    :param method_name: Name of the API method to be called. (E.g. 'getUpdates')
+    :param method: HTTP method to be used. Defaults to 'get'.
+    :param params: Optional parameters. Should be a dictionary with key-value pairs.
+    :param files: Optional files.
+    :return:
+    """
     request_url = telebot.API_URL + 'bot' + token + '/' + method_name
     result = requests.request(method, request_url, params=params, files=files)
     if result.status_code != 200:
-        raise ApiException(method_name + r' error.', result)
+        raise ApiException(method_name, result)
     try:
         result_json = result.json()
         if not result_json['ok']:
             raise Exception()
     except:
-        raise ApiException(method_name + r' error.', result)
+        raise ApiException(method_name, result)
     return result_json['result']
 
 
@@ -43,7 +52,7 @@ def send_message(token, chat_id, text, disable_web_page_preview=None, reply_to_m
     if reply_to_message_id:
         payload['reply_to_message_id'] = reply_to_message_id
     if reply_markup:
-        payload['reply_markup'] = convert_markup(reply_markup)
+        payload['reply_markup'] = _convert_markup(reply_markup)
     return _make_request(token, method_url, params=payload)
 
 
@@ -80,7 +89,7 @@ def send_photo(token, chat_id, photo, caption=None, reply_to_message_id=None, re
     if reply_to_message_id:
         payload['reply_to_message_id'] = reply_to_message_id
     if reply_markup:
-        payload['reply_markup'] = convert_markup(reply_markup)
+        payload['reply_markup'] = _convert_markup(reply_markup)
     return _make_request(token, method_url, params=payload, files=files, method='post')
 
 
@@ -90,7 +99,7 @@ def send_location(token, chat_id, latitude, longitude, reply_to_message_id=None,
     if reply_to_message_id:
         payload['reply_to_message_id'] = reply_to_message_id
     if reply_markup:
-        payload['reply_markup'] = convert_markup(reply_markup)
+        payload['reply_markup'] = _convert_markup(reply_markup)
     return _make_request(token, method_url, params=payload)
 
 
@@ -107,7 +116,7 @@ def send_data(token, chat_id, data, data_type, reply_to_message_id=None, reply_m
     if reply_to_message_id:
         payload['reply_to_message_id'] = reply_to_message_id
     if reply_markup:
-        payload['reply_markup'] = convert_markup(reply_markup)
+        payload['reply_markup'] = _convert_markup(reply_markup)
     return _make_request(token, method_url, params=payload, files=files, method='post')
 
 
@@ -122,13 +131,17 @@ def get_method_by_type(data_type):
         return 'sendVideo'
 
 
-def convert_markup(markup):
+def _convert_markup(markup):
     if isinstance(markup, types.JsonSerializable):
         return markup.to_json()
     return markup
 
 
 class ApiException(Exception):
-    def __init__(self, message, result):
-        super(ApiException, self).__init__(message)
+    """
+    This class represents an Exception thrown when a call to the Telegram API fails.
+    """
+    def __init__(self, function_name, result):
+        super(ApiException, self).__init__('{0} failed. Returned result: {1}'.format(function_name, result))
+        self.function_name = function_name
         self.result = result