code: def fromJobGraph(cls, jobGraph):
          
          return cls(jobStoreID=jobGraph.jobStoreID,
                     requirements=jobGraph._requirements,
                     command=jobGraph.command,
                     jobName=jobGraph.jobName,
                     unitName=jobGraph.unitName,
                     displayName=jobGraph.displayName,
                     predecessorNumber=jobGraph.predecessorNumber)
docs: Takes a job graph object and returns a job node object
          :param toil.jobGraph.JobGraph jobGraph: A job graph object to be transformed into a job node
          :return: A job node object
          :rtype: toil.job.JobNode