title: How to do column alignment in openpyxl?
body: <p>I am trying to align a column in openpyxl without success:</p>
  
  <pre><code>wb = Workbook()
  ws = wb.active
  </code></pre>
  
  <p>....</p>
  
  <pre><code>ws.column_dimensions["A"].alignment = Alignment(horizontal='left')
  ws.column_dimensions["C"].alignment = Alignment(horizontal='center')
  </code></pre>
  
  <p>The same for:</p>
  
  <pre><code>ws["A"].alignment = Alignment(horizontal='left')
  ws["C"].alignment = Alignment(horizontal='center')
  </code></pre>
  
  <p>This isn't working for me.<br>
  Otherwise, iterating though cells and do alignment works correctly!</p>