Internally, the module re uses 2 undocumented libraries: + sr | Python etc
Internally, the module re uses 2 undocumented libraries:
+ sre_parse to parse regular expressions into an abstract syntax tree. + sre_compile to compile parsed expression.
The first one can be used to see how a regexp was parsed by Python. There are many better tools and services (like regex101.com) to debug regular expressions but this one is already in the stdlib.