def get_columns(self, connection, table_name, schema=None, **kw):

        raise NotImplementedError()
utility routine to turn values into codes given the specified categories
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/engine/interfaces.py/Dialect.get_columns--crossover with--dataset/ETHPy150Open pydata/pandas/pandas/core/categorical.py/_get_codes_for_values