Create a base declarative class

def model_base(bind_label=None, info=None):
    """Create a base declarative class
    """
    Model = type('Model', (BaseModel,), {'__odm_abstract__': True})
    info = {}
    Model.__table_args__ = table_args(info=info)
    if bind_label:
        info['bind_label'] = bind_label
    return Model