title: python object typecasting
body: <p>Ive been trying search how to pass object reference in python and type cast it similar to Java but no to avail. I duno if this topic exists somewhere here. </p>
  
  <p>My trouble is i have to pass the object reference to a class constructor. But i duno how to typecast the reference to an object. In java though I have accomplish this but i have to transfer the code to the server side. </p>
  
  <p>many thanks,
  Jack</p>
  
  <pre><code>class SearchRectangle:
      def __init__(self, lower_left_subgrid_x, lower_left_subgrid_y, rectangle_width, rectangle_height):
  
          self.min_subgrid_x = int(lower_left_subgrid_x)
          self.max_subgrid_x = int(self.min_subgrid_x + rectangle_width -1)
          self.min_subgrid_y = int(lower_left_subgrid_y)
          self.max_subgrid_y = int(self.min_subgrid_y + rectangle_height -1)
  
       ...blah
  
  
  
  class SearchRectangleMultiGrid:
   # parent rectangle should be a SearchRectangle instance 
      def __init__(self, parent_rectangle):
          self.parent_rectangle = SearchRectangle()parent_rectangle
  
  
  
      # test codes
      test_rect = SearchRectangle(test_subgrid.subgrid_x, test_subgrid.subgrid_y, 18, 18)
      print "\n\nTest SearchRectangle";
      print test_rect.to_string()
      print test_rect.sql_clause
  
      test_rec_multi = SearchRectangleMultiGrid(test_rect)
      print "\n\nTest SearchRectangleMulti"
      test_rec_multi.parent_rectangle.to_string()
  </code></pre>