title: How to transform a polygon string on a real polygon
body: <p>I need some support to real a polygon. 
  Today I have a string and I need to change in a format that is possible to recognize as a polygon.</p>
  
  <p>I am acquiring directly from SQL the value of polygon:</p>
  
  <p>Example:</p>
  
  <p>I read on this way:</p>
  
  <pre><code>string = "POLYGON ((-47.158846224312285 -21.349760242365733;-47.158943117468695 -21.349706412900805;-47.159778541623055 -21.349008036758804))"
  </code></pre>
  
  <p>I need to change in this format</p>
  
  <pre><code>list = [(-47.158846224312285,  -21.349760242365733), (47.158943117468695 -21.349706412900805),  (-47.159778541623055, -21.349008036758804)]
  </code></pre>
  
  <p>Any idea how to modificate?</p>