def is_equivalent(self, type_=None, equivalent_type=None):
raise Unimplemented()<EOL>
Tests if the given types are equivalent.

        arg:    type (osid.type.Type): a type
        arg:    equivalent_type (osid.type.Type): another type
        return: (boolean) - true if both types are equivalent, false
                otherwise
        raise:  NullArgument - type is null
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        compliance: mandatory - This method must be implemented.