title: Add a transparent shape to an Excel file using Python/Openpyxl
body: <p>I have many different excel files, each with their own graph.  A portion of each graph is forecasted, and the rest of each graph is non-forecasted.  I was wondering if openpyxl had a method of opening an excel file, and creating a roughly 80% transparent shape (probably a rectangle) that I could place on top of the forecasted region of the chart.</p>
  <p>I can easily loop through each excel file to add the shape, I just need  to figure out how to do that for one file.  I've tried reading through openpyxl's documentation here:</p>
  <p><a href="https://openpyxl.readthedocs.io/en/2.4/api/openpyxl.drawing.shapes.html" rel="nofollow noreferrer">https://openpyxl.readthedocs.io/en/2.4/api/openpyxl.drawing.shapes.html</a></p>
  <p>But I'm having trouble understanding the documentation, and there are no simple examples to go off of.</p>
  <p>I've tried using xlsxwriter's insert_textbox method, but there is not way to make it ~80% transparent.  There is only 100% or 0% transparent.</p>