openpyxl 'TypeError: expected <class 'int'>' - excel

Question

Python 3.6 Newest openpyxl
So, I'm working with an excel using openpyxl. I have a very boring test.xlsx excel, which I can read with the following code:
import os
import openpyxl
wb = openpyxl.load_workbook('test.xlsx')
sheet = wb['Sheet1']
print(sheet)
However, when I change to a fairly complex excel document 'apqptest.xlsx.'
import os
import openpyxl
wb = openpyxl.load_workbook('apqptest.xlsx')
sheet = wb['Sheet1']
print(sheet)
I get the following error (I have created the same sheet1 on the apqptest.xlsx document just fyi):
C:\Users\nkent\PycharmProjects\webscraper\venv\Scripts\python.exe "C:/Users/nkent/Desktop/Programs/Quote Preperation.py"
Traceback (most recent call last):
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\descriptors\base.py", line 57, in _convert
value = expected_type(value)
TypeError: int() argument must be a string, a bytes-like object or a number, not 'NoneType'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "C:/Users/nkent/Desktop/Programs/Quote Preperation.py", line 3, in <module>
wb = openpyxl.load_workbook('apqptest.xlsx')
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\reader\excel.py", line 274, in load_workbook
for c in find_charts(archive, rel.target):
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\chart\reader.py", line 43, in find_charts
drawing = SpreadsheetDrawing.from_tree(tree)
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\descriptors\serialisable.py", line 84, in from_tree
obj = desc.expected_type.from_tree(el)
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\descriptors\serialisable.py", line 84, in from_tree
obj = desc.expected_type.from_tree(el)
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\descriptors\serialisable.py", line 84, in from_tree
obj = desc.expected_type.from_tree(el)
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\descriptors\serialisable.py", line 100, in from_tree
return cls(**attrib)
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\drawing\graphic.py", line 53, in __init__
self.rot = rot
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\descriptors\base.py", line 69, in __set__
value = _convert(self.expected_type, value)
File "C:\Users\nkent\PycharmProjects\webscraper\venv\lib\site-packages\openpyxl\descriptors\base.py", line 59, in _convert
raise TypeError('expected ' + str(expected_type))
TypeError: expected <class 'int'>