chel-ou

Compatibility issue with openpyxl 3.1.0 - read_sheet - TypeError: 'set' object is not subscriptable

7

Recent update of `openpyxl` to `3.1.0` breaks `read_sheet`. Below is the traceback ``` Traceback (most recent call last): File "/code/base/tests/tests.py", line 3318, in test_sheet sheet = pe.get_sheet( File "/opt/project/.venv/lib/python3.10/site-packages/pyexcel/core.py", line...