There are no environments named py-flake8, py-pydocstyle and py-apicheck.

* Use a thread-safe implementation of cached_property.

* Restore setter and deleter.

* Restore tests.

* Fix __get__ signature for backport.

* Cleanup.

Co-authored-by: Asif Saif Uddin <auvipy@gmail.com>

* handle sqs sts

* add doc

* use string format

* improve docs

* Update kombu/transport/SQS.py

Co-authored-by: Omer Katz <omer.drow@gmail.com>

* add helper method and tests

* changer to private

Co-authored-by: galcohen <gal.cohen@autodesk.com>
Co-authored-by: Asif Saif Uddin <auvipy@gmail.com>
Co-authored-by: Omer Katz <omer.drow@gmail.com>

- AMQPLAIN is only retained for backwards compatability and has become non-standard

* Clean up grammar in paragraph about callbacks

* Structure event draining examples into subsections

* Make code example make more sense

… and bring it more in line with text above.

* Fix code example

* Fix another code example

typo in method name

https://docs.python.org/3.9/whatsnew/3.0.html#library-changes

> A common pattern in Python 2.x is to have one version of a module implemented in pure Python, with an optional accelerated version implemented as a C extension; for example, pickle and cPickle. This places the burden of importing the accelerated version and falling back on the pure Python version on each user of these modules. In Python 3.0, the accelerated versions are considered implementation details of the pure Python versions. Users should always import the standard version, which attempts to import the accelerated version and falls back to the pure Python version. The pickle / cPickle pair received this treatment.