'Search for the username in 3 places
- public profile
- email
- name'

@classmethod
def _retrieve_facebook_username(cls, facebook_data):

    username = None
    link = facebook_data.get('link')
    if link:
        username = link.split('/')[(-1)]
        username = cls._make_username(username)
        if (username and ('profilephp' in username)):
            username = None
    if ((not username) and ('email' in facebook_data)):
        username = cls._make_username(facebook_data.get('email').split('@')[0])
    if ((not username) or (len(username) < 4)):
        username = cls._make_username(facebook_data.get('name'))
    if (not username):
        raise FacebookException('couldnt    figure    out    a    username')
    return username
