In case the number format of the cell contains a color definition such as
[Red], date format is incorrectly detected by the
is_date_format() function from the
This can lead to
ValueError on cell value retrieval if the cell contains a large or small enough number so that the Python
datetime.datetime date boundaries are exceeded.
Updating the line 95 of the module to
COLORS = "(\[black|blue|cyan|green|magenta|red|white|yellow\])"
fixes the problem (due to lowercasing of the format, this regex never matched previously).
This triggers an error: cell containing a number -781682,44 with a number format