@classmethod
def _add_workflow(mcs, field_name, state_field, attrs):
    """Attach the workflow to a set of attributes.

        Constructs the ImplementationWrapper for transitions, and adds them to
        the attributes dict.

        Args:
            field_name (str): name of the attribute where the StateField lives
            state_field (StateField): StateField describing that attribute
            attrs (dict): dictionary of attributes for the class being created
        """
    pass
