fix nest_lists for non-unique index

[dougbrn]

Fixes #334

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.13%. Comparing base (919fe82) to head (ad7a825).
⚠️ Report is 144 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #337   +/-   ##
=======================================
  Coverage   98.13%   98.13%           
=======================================
  Files          18       18           
  Lines        1774     1774           
=======================================
  Hits         1741     1741           
  Misses         33       33           

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[github-actions]

Before [919fe82]	After [9b52ecf]	Ratio	Benchmark (Parameter)
927M	994M	1.07	benchmarks.ReadFewColumnsS3.peakmem_run
44.6±0.8ms	45.1±0.5ms	1.01	benchmarks.ReassignHalfOfNestedSeries.time_run
250M	250M	1	benchmarks.AssignSingleDfToNestedSeries.peakmem_run
32.4±1ms	32.5±1ms	1	benchmarks.AssignSingleDfToNestedSeries.time_run
64.5±0.2ms	64.5±0.5ms	1	benchmarks.CountNestedBy.time_run
177M	176M	1	benchmarks.ReadFewColumnsHTTPS.peakmem_run
1.92±0.01s	1.93±0.03s	1	benchmarks.ReadFewColumnsHTTPS.time_run
270M	270M	1	benchmarks.ReassignHalfOfNestedSeries.peakmem_run
136M	135M	0.99	benchmarks.CountNestedBy.peakmem_run
103M	102M	0.99	benchmarks.NestedFrameAddNested.peakmem_run

Click here to view all benchmarks.

[gitosaurus]

Looks good!