README example uses tldextract.extract_urllib, but method is not exported

[vpolyakov]

Hi!
In the README section “How to validate URLs before extraction” the example uses:

result = tldextract.extract_urllib(split_url)

But in tldextract 5.3.1 this attribute does not exist at the module level.

Environment:

• Python: 3.13.9 (conda-forge) on macOS (darwin)
• tldextract: 5.3.1
• Installation: conda-forge
• tldextract.file:
  /Users/polyakov/miniforge3/envs/ju13/lib/python3.13/site-packages/tldextract/init.py

Repro:

import tldextract

print(tldextract.__version__)                      # 5.3.1
print(hasattr(tldextract, "extract_urllib"))       # False
print(hasattr(tldextract.TLDExtract, "extract_urllib"))  # True

Suggested fix (either option):
1. Update README to call it via an instance:

extractor = tldextract.TLDExtract()
result = extractor.extract_urllib(split_url)

or
2. Export a module-level wrapper tldextract.extract_urllib(...) for consistency with the README.

Thanks!