Improve modules and coverage

[mano8]

Changes:

• Improve code style
• Improve test coverage
• Correct api bugs

[mano8]

ok

[codecov]

Codecov Report

Attention: Patch coverage is 94.73684% with 3 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
emon_tools/api_utils.py	91.17%	0 Missing and 3 partials ⚠️

Files with missing lines	Coverage Δ
emon_tools/async_emon_api.py	78.80% <100.00%> (-0.28%)	⬇️
emon_tools/emon_api.py	93.28% <100.00%> (-0.10%)	⬇️
emon_tools/emon_api_core.py	96.60% <100.00%> (+18.10%)	⬆️
emon_tools/emonpy.py	91.66% <100.00%> (+28.85%)	⬆️
emon_tools/api_utils.py	93.63% <91.17%> (+16.90%)	⬆️

[mano8]

ok

[mano8]

ok