title: How to make holes in a Polygon in shapely python, having Polygons
body: <p>In python, I have a plain Polygon "outer" and a list of Polygons "inners". I want to make holes in my polygon using this list.</p>
  
  <pre><code>from shapely.geometry import Polygon
  
  # polygon with 1 hole in the middle
  p = Polygon(((0,0),(10,0),(10,10),(0,10)), (((4,4),(4,6),(6,6),(6,4)), ))
  print p.wkt
  # POLYGON ((0 0, 10 0, 10 10, 0 10, 0 0), (4 4, 4 6, 6 6, 6 4, 4 4))
  
  # other constructor, does not work (no hole) :
  outer = Polygon(((0,0),(10,0),(10,10),(0,10),(0,0)))
  inners = (Polygon(((4,4),(4,6),(6,6),(6,4),(4,4))), )
  p = Polygon(outer, inners)
  print p.wkt
  # POLYGON ((0 0, 10 0, 10 10, 0 10, 0 0))
  </code></pre>
  
  <p>How to build p given outer and inners ?</p>