code: def statistics(self):
          
          if self._statistics is None:
              self._statistics = WorkflowStatisticsList(
                  self._version,
                  workspace_sid=self._solution['workspace_sid'],
                  workflow_sid=self._solution['sid'],
              )
          return self._statistics
docs: Access the statistics
  
          :returns: twilio.rest.taskrouter.v1.workspace.workflow.workflow_statistics.WorkflowStatisticsList
          :rtype: twilio.rest.taskrouter.v1.workspace.workflow.workflow_statistics.WorkflowStatisticsList