@utilities.arguments_not_none<EOL><INDENT>def get_comments_by_parent_genus_type(self, comment_genus_type):<DEDENT>
<EOL>return objects.CommentList([])<EOL>
Gets a ``CommentList`` corresponding to the given comment genus ``Type`` and include any additional comments with genus types derived from the specified ``Type``.

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