如何在python中扫描脚本以查找上层脚本的返回值？

Question

import osimport pdbos.system("ToBuildOrNot.py MSS_sims")for output in os.system:     if ToBuildOrNot is True:         print "The MSS_sims Needs To rebuilt"     elif ToBuildOrNot is False:         print "The MSS_sism does NOT Need to be Rebuilt"     else:         print "error"