Oh, Python already accepts floating point numbers:

haypo@selma$ ./python
Python 3.7.0a1+ (heads/master-dirty:efb560eee2, Oct  3 2017, 12:15:58) 
[GCC 7.2.1 20170915 (Red Hat 7.2.1-2)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> re.compile("[a-z]", flags=re.I).match("A")
<_sre.SRE_Match object; span=(0, 1), match='A'>
>>> re.I
<RegexFlag.IGNORECASE: 2>
>>> re.compile("[a-z]", flags=2).match("A")
<_sre.SRE_Match object; span=(0, 1), match='A'>

# and now a float
>>> re.compile("[a-z]", flags=2.0).match("A")
<_sre.SRE_Match object; span=(0, 1), match='A'>