Fix bug that crashed table extraction when null value provided for (text|intersection)_(x|y)_tolerance keys

[samkit-jain]

Resolves bug raised in #539. The issue was happening because, in TableFinder, the settings were being cleaned up before the table extraction but in extract_table(s), the updated table settings were not being used and passing in None in the tolerance setting resulted in a comparison between numeric type and None type and that caused the exception. The issue was resolved by creating a static method to cleanup the user-provided table settings and using it for every operation post table extraction.

[codecov]

Codecov Report

Merging #545 (a806bfa) into develop (c915a00) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head a806bfa differs from pull request most recent head 608db02. Consider uploading reports for the commit 608db02 to get more accurate results

@@           Coverage Diff            @@
##           develop     #545   +/-   ##
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  Coverage    98.77%   98.77%           
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  Files           10       10           
  Lines         1220     1226    +6     
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+ Hits          1205     1211    +6     
  Misses          15       15           

Impacted Files	Coverage Δ
pdfplumber/page.py	100.00% <100.00%> (ø)
pdfplumber/table.py	100.00% <100.00%> (ø)

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[jsvine]

Thanks, @samkit-jain! I think it does make sense to do some settings cleanup/resolution, and so I'm definitely leaning toward merging this PR. But I wonder: Is it always safe to assume that a user passing None for a setting value means they want to use the default value? And if they want to use the default value, why pass the setting at all?

[samkit-jain]

I don't see any value in the settings that can have a meaningful null value and hence, think that the property not being provided or having the value as null can be treated the same. At https://github.com/jsvine/pdfplumber#table-extraction-settings, null value is being provided and that similar to in discussion #539 can confuse the users. We can also just remove the null and give those properties the default values.

[jsvine]

Thanks, @samkit-jain! That makes sense to me. And I agree: It's worth tweaking the README so that those None values in the table-settings documentation are listed as the default values. I can/will do that.