Round before formatting

[asmacdo]

If we don't do the rounding prior to formatting, the summary_format (being a format string, not an f-string) is not smart enough to handle floats OR None (or str 'unknown'). So instead we need to handle that first.

Fixes: #172
Fixes: #171

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.03%. Comparing base (2b12679) to head (b79229a).
Report is 26 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #181      +/-   ##
==========================================
+ Coverage   94.92%   95.03%   +0.10%     
==========================================
  Files           2        2              
  Lines         473      483      +10     
  Branches       73       75       +2     
==========================================
+ Hits          449      459      +10     
  Misses         12       12              
  Partials       12       12              

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[yarikoptic]

Frankly I don't like this as it spreads aspects of formatting now from format specification into the code. as for "unknown" I already gave a nice solution to again allow it to be float or None (not sure some ad-hoc string) and then being nicely formatted: then you keep value nicely pythonic Optional[float] and format it the way you like it. that is my 1c. and I gave already a dollar of those I think so far.