new_contents: #!/usr/bin/env python
  # encoding=utf-8
  
  class vector2d(object):
      def __init__(self, x, y):
          self.__x = float(x)
          self.__y = float(y)
      
      @property
      def x(self):
          return self.__x
      @property
      def y(self):
          return self.__y
  
      def __iter__(self):
          return (i for i in (self.x, self.y))
  
subject: make vector2d hashable