Delete a workflow from the database
        :param workflow_id:
        :return: None

def delete_workflow(self, workflow_id):
        """
        Delete a workflow from the database
        :param workflow_id:
        :return: None
        """
        deleted = False

        with switch_db(WorkflowDefinitionModel, "hyperstream"):
            workflows = WorkflowDefinitionModel.objects(workflow_id=workflow_id)
            if len(workflows) == 1:
                workflows[0].delete()
                deleted = True
            else:
                logging.debug("Workflow with id {} does not exist".format(workflow_id))

        with switch_db(WorkflowStatusModel, "hyperstream"):
            workflows = WorkflowStatusModel.objects(workflow_id=workflow_id)
            if len(workflows) == 1:
                workflows[0].delete()
                deleted = True
            else:
                logging.debug("Workflow status with id {} does not exist".format(workflow_id))

        if workflow_id in self.workflows:
            del self.workflows[workflow_id]
            deleted = True

        if deleted:
            logging.info("Deleted workflow with id {}".format(workflow_id))