Openpyxl error message. Help!

[Shafla]

Hi. I am following some text book lessons. I am trying to convert Column Letters to Numbers and getting the following error message.

>>> import openpyxl
>>> from openpyxl.cell import get_column_letter, column_index_from_string
Traceback (most recent call last):
  File "<pyshell#82>", line 1, in <module>
    from openpyxl.cell import get_column_letter, column_index_from_string
ImportError: cannot import name 'get_column_letter' from 'openpyxl.cell' (/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/openpyxl/cell/__init__.py)