code: def add_page(self, page, process_id, wit_ref_name):
          
          route_values = {}
          if process_id is not None:
              route_values['processId'] = self._serialize.url('process_id', process_id, 'str')
          if wit_ref_name is not None:
              route_values['witRefName'] = self._serialize.url('wit_ref_name', wit_ref_name, 'str')
          content = self._serialize.body(page, 'Page')
          response = self._send(http_method='POST',
                                location_id='1cc7b29f-6697-4d9d-b0a1-2650d3e1d584',
                                version='5.0-preview.1',
                                route_values=route_values,
                                content=content)
          return self._deserialize('Page', response)
docs: AddPage.
          [Preview API] Adds a page to the work item form.
          :param :class:`<Page> <azure.devops.v5_0.work_item_tracking_process.models.Page>` page: The page.
          :param str process_id: The ID of the process.
          :param str wit_ref_name: The reference name of the work item type.
          :rtype: :class:`<Page> <azure.devops.v5_0.work_item_tracking_process.models.Page>`