sre_constants.error: redefinition of group name 'remote_addr' as group 17; was group 3

[oppianmatt]

Traceback (most recent call last):
  File "/usr/local/bin/ngxtop", line 11, in <module>
    sys.exit(main())
  File "/usr/local/lib/python2.7/dist-packages/ngxtop/ngxtop.py", line 385, in main
    process(args)
  File "/usr/local/lib/python2.7/dist-packages/ngxtop/ngxtop.py", line 367, in process
    pattern = build_pattern(log_format)
  File "/usr/local/lib/python2.7/dist-packages/ngxtop/config_parser.py", line 137, in build_pattern
    return re.compile(pattern)
  File "/usr/lib/python2.7/re.py", line 190, in compile
    return _compile(pattern, flags)
  File "/usr/lib/python2.7/re.py", line 242, in _compile
    raise error, v # invalid expression
sre_constants.error: redefinition of group name 'remote_addr' as group 17; was group 3