==> git log -n1 <==
commit 67a89c78871b234ffad53b23e8e4a76bf1fe766c
Author: Ray Donnelly <mingw.android@gmail.com>
Date:   Sun Apr 29 23:50:02 2018 +0100

    Python 3.7 compat: Properly escape repl in re.sub
    
    With python -c "import re; print(re.sub(r'\s+',r'\s*','      here are  some   words'))"
    
    Python 2.7 and 3.6 give:
    ```
    \s*here\s*are\s*some\s*words
    ```
    
    While Python 3.7 gives:
    ```
    Traceback (most recent call last):
      File "/opt/conda/envs/py37/lib/python3.7/sre_parse.py", line 1021, in parse_template
        this = chr(ESCAPES[this][1])
    KeyError: '\\s'
    
    During handling of the above exception, another exception occurred:
    
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/opt/conda/envs/py37/lib/python3.7/re.py", line 192, in sub
        return _compile(pattern, flags).sub(repl, string, count)
      File "/opt/conda/envs/py37/lib/python3.7/re.py", line 309, in _subx
        template = _compile_repl(template, pattern)
      File "/opt/conda/envs/py37/lib/python3.7/re.py", line 300, in _compile_repl
        return sre_parse.parse_template(repl, pattern)
      File "/opt/conda/envs/py37/lib/python3.7/sre_parse.py", line 1024, in parse_template
        raise s.error('bad escape %s' % this, len(this))
    re.error: bad escape \s at position 0
    ```
    
    From https://docs.python.org/3.7/whatsnew/3.7.html
    .. this change in behaviour seems to be due to:
    ```
    Unknown escapes consisting of '\' and an ASCII letter in replacement templates for
    re.sub() were deprecated in Python 3.5, and will now cause an error.
    ```
    
    The URL for this bug is:
    https://bugs.python.org/issue27030
    
    And the commit is:
    https://github.com/python/cpython/commit/9bd85b83f66d31e39282244e455275bd9cd91bb1
==> git describe --tags --dirty <==
v0.23.2-1-g67a89c7
==> git status <==
HEAD detached from v0.23.2
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