code: def _get_column_and_bindparam(left, right, operator):
      
      if not isinstance(left, Column):
          left, right = right, left
      if not isinstance(left, Column):
          raise AssertionError(
              u'SQLAlchemy operator {} expects Column as left side the of expression, got {} '
              u'of type {} instead.'.format(operator, left, type(left)))
      if not isinstance(right, BindParameter):
          raise AssertionError(
              u'SQLAlchemy operator {} expects BindParameter as the right side of the expression, '
              u'got {} of type {} instead.'.format(operator, right, type(right)))
      return left, right
docs: Return left and right expressions in (Column, BindParameter) order.