@classmethod
def _create(cls, target_class, *args, **kwargs):
    """Create an instance of the model, and save it to the database."""
    from mogwai.models import Edge
    if issubclass(target_class.__class__, Edge):
        assert 'outV' in kwargs and 'inV' in kwargs, 'Edges require in and out Vertices'
        obj = target_class.create(*args, outV=kwargs.get('outV'), inV=
            kwargs.get('inV'), **kwargs)
    else:
        obj = target_class.create(*args, **kwargs)
    return obj
