Traceback when running lunch -k about lunch HOT 1 OPEN

There is an error in your lunch file !
Traceback (most recent call last):
  File "/home/odroid/src/lunch/lunch/runner.py", line 136, in run
    lunch_master = master.run_master(config_file,
  File "/home/odroid/src/lunch/lunch/master.py", line 858, in run_master
    pid_file = write_master_pid_file(identifier=master_identifier, directory=pid_dir)
  File "/home/odroid/src/lunch/lunch/master.py", line 620, in write_master_pid_file
    pid = is_lunch_master_running(pid_file)
  File "/home/odroid/src/lunch/lunch/master.py", line 596, in is_lunch_master_running
    if "python" in output:
TypeError: a bytes-like object is required, not 'str'