* Attempt 2 of cert validation fixes
* Remove unused code
* Cleanup the tmp cert using atexit
* Fix linting issues
* Only add SSLValidationHandler when not HAS_SSLCONTEXT
* Catch value errors on non PEM certs
* Only catch NotImplementedError to avoid masking issues
* set self._context even with PyOpenSSLContext for conformity
* Fix error building
* normalize how we interact with the context we create
* Remove unused code
* Address test for py3.7 message difference
* open_url should pass the ca_path through
* Account for new error in url lookup test
* Guard some code behind whether or not we are validating certs
* Make _make_context public
* Move atexit.register up to where the tmp file is created
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