remove old code since all arguments are quoted now and the code was not
being used, add coverage exclusion on some code that should never be
executed and add an additional test
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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Fixes#890
Add parsing of environmental variables when supplied for the config file
option.
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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
