What's the best way to format a phone number in Python?

Question

If all I have is a string of 10 or more digits, how can I format this as a phone number?

Some trivial examples:

555-5555
555-555-5555
1-800-555-5555

I know those aren't the only ways to format them, and it's very likely I'll leave things out if I do it myself. Is there a python library or a standard way of formatting phone numbers?

Answer 1

for library: phonenumbers (pypi, source)

Python version of Google's common library for parsing, formatting, storing and validating international phone numbers.

The readme is insufficient, but I found the code well documented.