Example of type coercion for sqlalchemy.

gistfile1.py

class CoerceDateTime(TypeDecorator):
    """Extend DateTime to also coerce iso formatted datetime strings and epoch
    ints in addition to native python datetimes"""

    impl = DateTime

    def process_bind_param(self, value, dialect):
        if isinstance(value, str):
            try:
                value = iso8601.parse_date(value)
            except:
                pass
        if isinstance(value, int):
            try:
                value = datetime.datetime.fromtimestamp(value)
            except:
                pass
        return value

postgres.ischema_names['timestamp'] = CoerceDateTime
postgres.ischema_names['timestamp with time zone'] = CoerceDateTime
postgres.ischema_names['timestamp without time zone'] = CoerceDateTime
postgres.ischema_names['timestamp'] = CoerceDateTime