Calls DataAccess.find and passes the results to the given constructor.

def _find_model(self, constructor, table_name, constraints=None, *, columns=None, order_by=None):
    """Calls DataAccess.find and passes the results to the given constructor."""
    data = self.find(table_name, constraints, columns=columns, order_by=order_by)
    return constructor(data) if data else None