Bug Description:
Deprecation warnings are issued by Python for the following changes:
1. https://docs.python.org/3/whatsnew/3.6.html#deprecated-python-behavior
https://bugs.python.org/issue27364 - Deprecate invalid escape sequences in str/bytes
2. https://docs.python.org/3/whatsnew/3.7.html#deprecated-python-behavior
https://bugs.python.org/issue25988 - collections.abc.Indexable
3. https://docs.python.org/3/library/logging.html#logging.warning
https://bugs.python.org/issue13235 - logging.warn() is not documented

Fix Description:
1. Use correct escape sequences or raw strings where needed.
2. Import Callable from collections.abc instead of collections module directly.
3. Use logging.warning() instead of logging.warn().

https://pagure.io/389-ds-base/issue/50032

Reviewed by: ???