fetches friend email's from g+

        Return:
            collection of friend emails (ids)

def fetch_friend_ids(self, user):
        """
        fetches friend email's from g+

        Return:
            collection of friend emails (ids)
        """
        friends = self.fetch_friends(user)

        return [friend['ns1_email']['address']
                for friend in friends
                if 'ns1_email' in friend]