Seeking regex optimizer

[Kay Schluehr]

I have a list of strings ls = [s_1,s_2,...,s_n] and want to create a
regular expression sx from it, such that sx.match(s) yields a SRE_Match
object when s starts with an s_i for one i in [0,...,n].  There might
be relations between those strings: s_k.startswith(s_1) -> True or
s_k.endswith(s_1) -> True. An extreme case would be ls = ['a', 'aa',
...,'aaaa...ab']. For this reason SRE_Match should provide the longest
possible match.

Is there a Python module able to create an optimized regex rx from ls
for the given constraints?

Regards,
Kay