:param attribute_name: name of the mapped attribute to inspect.
        :returns: list of 2-tuples containing information about the inspected
          attribute (first element: mapped entity attribute kind; second
          attribute: mapped entity attribute)

def inspect(orm_class, attribute_name):
        """
        :param attribute_name: name of the mapped attribute to inspect.
        :returns: list of 2-tuples containing information about the inspected
          attribute (first element: mapped entity attribute kind; second
          attribute: mapped entity attribute)
        """
        key = (orm_class, attribute_name)
        elems = OrmAttributeInspector.__cache.get(key)
        if elems is None:
            elems = OrmAttributeInspector.__inspect(key)
            OrmAttributeInspector.__cache[key] = elems
        return elems