fethces friend id's from twitter

        Return:
            collection of friend ids

def fetch_friend_ids(self, user):
        """
        fethces friend id's from twitter

        Return:
            collection of friend ids
        """
        friends = self.fetch_friends(user)
        friend_ids = []
        for friend in friends:
            friend_ids.append(friend.id)
        return friend_ids