Enable the pylint checks:
  * unnecessary-pass
  * unspecified-encoding

Update code to resolve errors found

Enabled the pylint checks that don't require any code changes.
Previously these checks were disabled.

Enable the pylint check "raise-missing-from" and fix errors detected.

Enable the pylint check: "attribute-defined-outside-init" and fix
errors detected.

Enable the pylint check "no-else-return" and fix the errors detected.

Enable the pylint check "no-self-use" and fix the errors detected.

Enable the pylint check "redefined-outer-name" and fix the errors
detected.