`url2purl` does not make purls for the following PyPI URLs - https://files.pythonhosted.org/packages/84/d8/451842a5496844bb5c7634b231a2e4caf0d867d2e25f09b840d3b07f3d4b/multi_key_dict-2.0.win32.exe - https://pypi.python.org/packages/any/s/setuptools/setuptools-0.6c11-1.src.rpm - https://pypi.python.org/packages/2.6/t/threadpool/threadpool-1.2.7-py2.6.egg