title: Return list of all cell addresses within a Range
body: <p>I have a list of Ranges (loaded from an Excel workbook via openpyxl) in a list (e.g., <code>rng_list = ['$A$1:$A$3', '$B$1:$B$3', '$C$1:$C$3']</code>) and I would like to "unpack" each of those ranges into separate lists within a list of lists (i.e., <code>unpacked_list = [['$A$1','$A$2','$A$3'], ['$B$1','$B$2','$B$3'], ['$C$1','$C$2','$C$3']]</code>).</p>
  
  <p>Please see the code below on what I have tried so far in a Jupyter Notebook. Any thoughts on why I am getting the error below? or if you have ideas on how I might want to approach this from a different angle, that would be much appreciated! Thanks! </p>
  
  <pre><code>    import os
      from openpyxl import Workbook
      from openpyxl.utils import get_column_letter
  
      # create temp worksheet
      wb_A = Workbook() 
      sheet_A = wb_A.create_sheet('sheetA')
  
      # list with Excel ranges as str items in list
      rng_list = ['$A$1:$B$10', '$C$1:$D$10', '$E$1:$F$10']
      temp_list = []
      unpacked_list = []
  
  
      for item in rng_list:
          for row in sheet_A(item): # use range from item in rng_list to iterate 
                                      through range in temp worksheet
              for cell in row:
                  x = cell.row
                  y = cell.column
                  addr = get_column_letter(y) + str(x)
                  temp_list.append(addr)
              unpacked_list.append(addr)
  
      # delete temp worksheet
      wb_A.remove(sheet_A)
  
      unpacked_list
  </code></pre>
  
  <p>I was hoping to use the range str from the list to iterate through a "dummy worksheet" created just to iterate through the cell range and capture the corresponding cell addresses within the range. I get the following error:</p>
  
  <pre><code>---------------------------------------------------------------------------
  TypeError                                 Traceback (most recent call last)
  &lt;ipython-input-85-13b28d369550&gt; in &lt;module&gt;
       14 
       15 for item in rng_list:
  ---&gt; 16     for row in sheet_A(item): # use range from item in rng_list to iterate through range in temp worksheet
       17         for cell in row:
       18             x = cell.row
  
  TypeError: 'Worksheet' object is not callable
  </code></pre>