def get_calendar_conversion_session_for_type(self, source_calendar_type=None, source_time_type=None, target_calendar_type=None, target_time_type=None):
Gets an ``OsidSession`` associated with the calendar conversion service and the given calendar types.

        arg:    source_calendar_type (osid.type.Type): the type of the
                source calendar
        arg:    source_time_type (osid.type.Type): the type of the
                source time
        arg:    target_calendar_type (osid.type.Type): the type of the
                target calendar
        arg:    target_time_type (osid.type.Type): the type of the
                target time
        return: (osid.locale.CalendarConversionSession) - a
                ``CalendarConversionSession``
        raise:  NullArgument - ``source_calendar_type,
                source_time_type,``  ``target_calendar_type`` or
                ``target_time_type`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - ``supports_calendar_conversion()`` or
                ``supports_visible_federation()`` is ``false``
        raise:  Unsupported -
                ``supports_calendar_types_for_conversion(source_calendar
                _type, target_calendar_type)`` or
                ``supports_time_types_for_conversion(source_time_type,
                target_time_type)`` is ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_calendar_conversion()`` and
        ``supports_visible_federation()`` are ``true``.*