def METHOD_NAME(self, item, identity_field=None):
    # email not available for gitter
    identity = {
        'username': None,
        'name': None,
        'email': None
    }
    if self.get_field_author() not in item['data']:
        return identity
    from_ = item['data'][self.get_field_author()]
    identity['username'] = from_.get('username', None)
    identity['name'] = from_.get('displayName', None)
    return identity