def get_repositories_by_parent_genus_type(self, repository_genus_type=None):
pass<EOL>
Gets a ``RepositoryList`` corresponding to the given repository genus
        ``Type`` and include any additional repositories with genus types
        derived from the specified ``Type``.

        In plenary mode, the returned list contains all known
        repositories or an error results. Otherwise, the returned list
        may contain only those repositories that are accessible through
        this session.

        arg:    repository_genus_type (osid.type.Type): a repository
                genus type
        return: (osid.repository.RepositoryList) - the returned
                ``Repository list``
        raise:  NullArgument - ``repository_genus_type`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*