Python Polars 0.16.5

🚀 Performance improvements

• speedup quantile/median ~2x (#6861)
• remove unneeded series allocations in groupby aggs (#6855)

✨ Enhancements

• restore dataframe class (#6869)
• add include_index option on init from pandas frames (#6847)
• properly implement null array (#6817)
• avoid panic error in strftime with invalid format (#6810)

🐞 Bug fixes

• fix crash in write_csv when mixed tz-naive and tz-aware datetimes are present (#6828)
• accept more types in groupby.agg (#6709)
• Fix pl.from_dataframe() as pyarrow.interchange was not i… (#6844)
• fix schema of functions: (#6845)
• stabilize integer operation to minimal required dtype (#6841)
• use explicit type-arg for PythonDataType (#6481)
• fix numpy/datetime regression (#6835)
• implement to_list for null dtype (#6834)
• Raise ValueError on passing multiple expressions Numpy ufunc (#6821)
• respect schema in ndjson (#6819)

🛠️ Other improvements

• Fail tests on warning (#6868)
• further improve struct expr docstrings (#6852)
• Deprecate non-keyword args for some functions (#6851)
• un-skip passing test (#6854)
• parenthesise col type signature to improve hint interaction with PyCharm (#6850)
• Deprecate positional join args (#6826)
• Rename argsort/argsort_by to arg_sort/arg_sort_by (#6829)
• Update dprint config excludes (#6822)
• Fix some broken noqa comments (#6823)
• Run mypy as part of the lint workflow (#6820)
• various minor docstring rendering fixes (#6818)
• fix lazy groupby docstring/rendering (#6816)

Thank you to all our contributors for making this release possible!
@MarcoGorelli, @alexander-beedie, @ghuls, @josh, @kngwyu, @oysols, @ritchie46, @stinodego and @zundertj