code: def get_process_work_item_type(self, process_id, wit_ref_name, expand=None):
          
          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')
          query_parameters = {}
          if expand is not None:
              query_parameters['$expand'] = self._serialize.query('expand', expand, 'str')
          response = self._send(http_method='GET',
                                location_id='e2e9d1a6-432d-4062-8870-bfcb8c324ad7',
                                version='5.0-preview.2',
                                route_values=route_values,
                                query_parameters=query_parameters)
          return self._deserialize('ProcessWorkItemType', response)
docs: GetProcessWorkItemType.
          [Preview API] Returns a single work item type in a process.
          :param str process_id: The ID of the process
          :param str wit_ref_name: The reference name of the work item type
          :param str expand: Flag to determine what properties of work item type to return
          :rtype: :class:`<ProcessWorkItemType> <azure.devops.v5_0.work_item_tracking_process.models.ProcessWorkItemType>`