code: def assign_job_record(self, tree_node):
          
          try:
              job_record = self.job_dao.get_one(tree_node.process_name, tree_node.timeperiod)
          except LookupError:
              state_machine_name = context.process_context[tree_node.process_name].state_machine_name
              state_machine = self.state_machines[state_machine_name]
              job_record = state_machine.create_job(tree_node.process_name, tree_node.timeperiod)
          tree_node.job_record = job_record
docs: - looks for an existing job record in the DB, and if not found
              - creates a job record in STATE_EMBRYO and bind it to the given tree node