$ python3 --version
Python 3.6.8
$ pip3 list --format=legacy |grep semver
semver (2.9.0)
$ python3
Python 3.6.8 (default, Oct  7 2019, 12:59:55) 
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import semver
>>> semver.parse('0.1.0-20191919191919.1fe6b123')
{'major': 0, 'minor': 1, 'patch': 0, 'prerelease': '20191919191919.1fe6b123', 'build': None}
>>> semver.parse('0.1.0-20191919191919.0fe6b123')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ezlukga/.local/lib/python3.6/site-packages/semver.py", line 72, in parse
    raise ValueError('%s is not valid SemVer string' % version)
ValueError: 0.1.0-20191919191919.0fe6b123 is not valid SemVer string
>>> semver.parse('0.1.0-20191919191919.0f')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ezlukga/.local/lib/python3.6/site-packages/semver.py", line 72, in parse
    raise ValueError('%s is not valid SemVer string' % version)
ValueError: 0.1.0-20191919191919.0f is not valid SemVer string
>>> semver.parse('0.1.0-0f')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ezlukga/.local/lib/python3.6/site-packages/semver.py", line 72, in parse
    raise ValueError('%s is not valid SemVer string' % version)
ValueError: 0.1.0-0f is not valid SemVer string