@abc.abstractmethod<EOL><INDENT>def create_calendar(self, calendar_form):<DEDENT>
return<EOL>
Creates a new ``Calendar``.

        :param calendar_form: the form for this ``Calendar``
        :type calendar_form: ``osid.calendaring.CalendarForm``
        :return: the new ``Calendar``
        :rtype: ``osid.calendaring.CalendarForm``
        :raise: ``IllegalState`` -- ``calendar_form`` already used for a create transaction
        :raise: ``InvalidArgument`` -- one or more of the form elements is invalid
        :raise: ``NullArgument`` -- ``calendar_form`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure
        :raise: ``Unsupported`` -- ``calendar_form`` did not originate from ``get_calendar_form_for_create()``

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