@abc.abstractmethod<EOL><INDENT>def get_types(self):<DEDENT>
return<EOL>
Gets all the known Types.

        :return: the list of all known ``Types``
        :rtype: ``osid.type.TypeList``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

        *compliance: mandatory -- This method must be implemented.*