Nnsuds

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* Restore last_sent and last_received functions

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* Use usedforsecurity=False for md5() calls to make suds work on FIPS compliant python

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* Fix undeclared variables, found via linting.
* Allow subclassing Builder to always initialize optional arrays with empty lists
* [ci] Drop py3.6 testing, add 3.10
* Allow subclasses of Builder to determine if children are initialized.
* Don't ignore underscore prefixed attribute

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* Drop support for python 2.x

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* R4201 Any PASSWORD MUST specify a Type attribute
* Compress or decompress message when Content-Encoding is present in headers
* Do not force byte-compilation optimization at level 1

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* Add per invocation timeout
* Ensure request headers set in options are used to fetch definitions