code: def get_process_mapping():
      
      output = subprocess.check_output([
          'ps', '-ww', '-o', 'pid=', '-o', 'ppid=', '-o', 'args=',
      ])
      if not isinstance(output, str):
          output = output.decode(sys.stdout.encoding)
      processes = {}
      for line in output.split('\n'):
          try:
              pid, ppid, args = line.strip().split(None, 2)
          except ValueError:
              continue
          processes[pid] = Process(
              args=tuple(shlex.split(args)), pid=pid, ppid=ppid,
          )
      return processes
docs: Try to look up the process tree via the output of `ps`.