@classmethod
def update_user(cls, **kwargs):
    """ Update a user with the available parameters.

        >>> user = Retaincc.get_user(user_id='123')
        >>> user['name']
        u'Somebody'
        >>> user = Retaincc.update_user(user_id='123', name='Guido')
        >>> user['name']
        u'Guido'

        """
    return cls._do_call('PUT', cls.api_endpoint + 'users', params=kwargs)
