👕 Code refinement

[chfw]

Before raising the PR, here is a check list:

• have you written unit tests for your code changes?
• have you updated the change log?
• can someone else understand your changes without your explanation?
• are you proud of your code changes?
• please add your name and github link to contributors.rst in alphabetical order.

[codecov-io]

Codecov Report

Merging #342 into dev will decrease coverage by 0.01%.
The diff coverage is 97.95%.

@@            Coverage Diff             @@
##              dev     #342      +/-   ##
==========================================
- Coverage   95.97%   95.96%   -0.02%     
==========================================
  Files          51       50       -1     
  Lines        2632     2625       -7     
==========================================
- Hits         2526     2519       -7     
  Misses        106      106

Impacted Files	Coverage Δ
tests/mobanfile/test_mobanfile.py	100% <ø> (ø)	⬆️
tests/test_reporter.py	100% <ø> (ø)	⬆️
moban/externals/reporter.py	96.15% <ø> (ø)	⬆️
...sts/integration_tests/test_command_line_options.py	99.69% <ø> (ø)	⬆️
tests/test_hash_store.py	98.63% <ø> (ø)	⬆️
tests/test_buffered_writer.py	100% <ø> (ø)	⬆️
moban/core/utils.py	94.44% <ø> (+1.85%)	⬆️
tests/mobanfile/test_templates.py	100% <ø> (ø)	⬆️
tests/test_copy_engine.py	100% <ø> (ø)	⬆️
tests/test_definitions.py	100% <ø> (ø)	⬆️
... and 19 more

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