'Takes session saved data to continue pipeline and merges with any
new extra argument needed. Returns tuple with next pipeline index
entry, arguments and keyword arguments to continue the process.'

def from_session_dict(self, session_data, *args, **kwargs):

    args = (args[:] + tuple(map(ctype_to_model, session_data['args'])))
    kwargs = kwargs.copy()
    saved_kwargs = dict(((key, ctype_to_model(val)) for (key, val) in six.iteritems(session_data['kwargs'])))
    saved_kwargs.update(((key, val) for (key, val) in six.iteritems(kwargs)))
    return (session_data['next'], args, saved_kwargs)
