UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Firefox/60.0

Steps to reproduce the problem:
1. git clone https://chromium.googlesource.com/deps/inspector_protocol
2. flake8 . --select=E901,E999,F821,F822,F823 --show-source
3. 

What is the expected behavior?
Inspector protocol would be compatible with the current release of Python.

What went wrong?
Flake8 testing of inspector protocol
* print() is a function in Python 3
* xrange() was removed in Python 3 in favor of a reworked version of range()

./check_protocol_compatibility.py:478:46: E999 SyntaxError: invalid syntax
            print "  Public changes since %s:" % version
                                             ^
./code_generator.py:43:18: F821 undefined name 'xrange'
        for i in xrange(len(keys)):
                 ^
./pdl.py:162:51: E999 SyntaxError: invalid syntax
        print 'Error in %s:%s, illegal token: \t%s' % (file_name, i, line)
                                                  ^
2     E999 SyntaxError: invalid syntax
1     F821 undefined name 'xrange'
3

Did this work before? No 

Chrome version: <Copy from: 'about:version'>  Channel: n/a
OS Version: OS X 10.14
Flash Version: Shockwave Flash 32.0 r0