xlsxwriter does not accept TSV or CSV extension

[broncio123]

A similar behaviour is observed when adding a TSV extension.

Excel spreadsheets are non-human readable.
It is always easier to load a CSV or TSV file into Excel than loading a spreadsheet for downstream analysis with Python.

Can we revert to the previous behaviour?

# Command: python mutation_analysis.py --alignment data/BACT000002.aln --type n --frame 1 --output output.csv
Starting Mutation Analysis
Parsing nucleotide alignment from: data/BACT000002.aln
Alignment length: 768
Analyzing nucleotide alignment (syn/non-syn)...
Writing output to output.csv
Traceback (most recent call last):
  File "/home/broncio/oxford/genescan/caro_project/mutation_analysis.py", line 635, in <module>
    main()
  File "/home/broncio/oxford/genescan/caro_project/mutation_analysis.py", line 625, in main
    write_output(
  File "/home/broncio/oxford/genescan/caro_project/mutation_analysis.py", line 516, in write_output
    with pd.ExcelWriter(output_file, engine='xlsxwriter') as writer:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/broncio/anaconda3/lib/python3.12/site-packages/pandas/io/excel/_xlsxwriter.py", line 204, in __init__
    super().__init__(
  File "/home/broncio/anaconda3/lib/python3.12/site-packages/pandas/io/excel/_base.py", line 1221, in __init__
    self.check_extension(ext)
  File "/home/broncio/anaconda3/lib/python3.12/site-packages/pandas/io/excel/_base.py", line 1340, in check_extension
    raise ValueError(f"Invalid extension for engine '{cls.engine}': '{ext}'")
ValueError: Invalid extension for engine '<property object at 0x79f821769710>': 'csv'

[kjolley]

I think it would be preferable to have both Excel output as well as a text format if possible.