Strange failure to determine `string` dtype column in ODS sheet/file

[alexander-beedie]

Attached two visually-identical files below that can be used to reproduce the issue. Both appear to contain identical column data, but one fails to load while the other succeeds.

⬇️ success.ods ⬇️ failure.ods

Example:

import fastexcel as xl

xl.read_excel("success.ods").load_sheet(0)
# ExcelSheet<Test>

xl.read_excel("failure.ods").load_sheet(0)
# CannotRetrieveCellDataError: cannot retrieve cell data at (8, 0)
# Context:
#     0: could not determine dtype for column StringCol