title: openpyxl 'TypeError: expected <class 'int'>'
body: <p>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:</p>
  
  <pre><code>import os
  import openpyxl
  wb = openpyxl.load_workbook('test.xlsx')
  sheet = wb['Sheet1']
  print(sheet)
  </code></pre>
  
  <p>However, when I change to a fairly complex excel document 'apqptest.xlsx.'</p>
  
  <pre><code>import os
  import openpyxl
  wb = openpyxl.load_workbook('apqptest.xlsx')
  sheet = wb['Sheet1']
  print(sheet)
  </code></pre>
  
  <p>I get the following error (I have created the same sheet1 on the apqptest.xlsx document just fyi):</p>
  
  <pre><code> 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 &lt;module&gt;
          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 &lt;class 'int'&gt;
  </code></pre>