Polars: py-0.15.9 Release

🚀 Performance improvements

• improve reducing window function performance ~33% (#5878)

✨ Enhancements

• str.strip with multiple chars (#5929)
• add iterrrows (#5945)
• read decimal as f64 (#5938)
• improve query plan scan formatting (#5937)
• allow all null cast (#5933)
• allow objects in struct types (#5925)
• handle Series init from python sequence of numpy arrays (#5918)
• merge sorted dataframes (#5817)
• impl hex and base64 for binary (#5892)
• Add datatype hierarchy (#5901)
• Add .item() on DataFrame and Series (#5893)
• make get_any_value fallible (#5877)
• Add string representation for data types (#5861)
• directly push all operator result into sink, prev… (#5856)

🐞 Bug fixes

• don't panic on ignored context (#5958)
• don't allow named expression in arr.eval (#5957)
• error on invalid dtype (#5956)
• fix panic in join expressions (#5954)
• block ordered predicates before explode (#5951)
• adhere to schema in arr.eval of empty list (#5947)
• fix from_dict schema_inference=0 (#5948)
• fix arrow nested null conversion (#5946)
• allow None in arr.slice length (#5934)
• fix time to duration cast (#5932)
• error on addition with datetime/time (#5931)
• don't create categoricals in streaming (#5926)
• object filter should keep single chunk (#5913)
• csv, read escaped "" as missing (#5912)
• fix pivot of signed integers (#5909)
• don't allow duplicate columns in read_csv arg (#5908)
• fix latest oob in streaming convertion (#5902)
• adapt k to len in topk (#5888)
• fix lazy swapping rename (#5884)
• fix window function with nullable values; regression due… (#5874)
• improve equality consistency between types (#5873)
• evaluate whole branch expression to determine if r… (#5864)
• fix top_k on empty (#5865)
• fix slice in streaming (#5854)
• Fix type hint for IO *_options arguments (#5852)

🛠️ Other improvements

• Fix docs for sink_parquet (#5952)
• Fix misspelling in LazyFrame docstring (#5917)
• add bin, series.is_sorted and merge_sorted (#5914)

Thank you to all our contributors for making this release possible! @AnatolyBuga, @alexander-beedie, @cannero, @chitralverma, @dannyvankooten, @johngunerli, @ozgrakkurt, @ritchie46, @stinodego, @winding-lines and @zundertj