old_contents: from __future__ import unicode_literals
  
  from itertools import product
  from collections import defaultdict
  
  __all__ = (
      'MouseHandlers',
  )
  
  
  class MouseHandlers(object):
      """
      Two dimentional raster of callbacks for mouse events.
      """
      def __init__(self):
          def dummy_callback(mouse_event):
              """
              :param mouse_event: `MouseEvent` instance.
              """
  
          # Map (x,y) tuples to handlers.
          self.mouse_handlers = defaultdict(lambda: dummy_callback)
  
      def set_mouse_handler_for_range(self, x_min, x_max, y_min, y_max, handler=None):
          """
          Set mouse handler for a region.
          """
          for x, y in product(range(x_min, x_max), range(y_min, y_max)):
              self.mouse_handlers[x, y] = handler
  
new_contents: from __future__ import unicode_literals
  
  from itertools import product
  from collections import defaultdict
  
  __all__ = (
      'MouseHandlers',
  )
  
  
  class MouseHandlers(object):
      """
      Two dimensional raster of callbacks for mouse events.
      """
      def __init__(self):
          def dummy_callback(mouse_event):
              """
              :param mouse_event: `MouseEvent` instance.
              """
  
          # Map (x,y) tuples to handlers.
          self.mouse_handlers = defaultdict(lambda: dummy_callback)
  
      def set_mouse_handler_for_range(self, x_min, x_max, y_min, y_max, handler=None):
          """
          Set mouse handler for a region.
          """
          for x, y in product(range(x_min, x_max), range(y_min, y_max)):
              self.mouse_handlers[x, y] = handler
  
subject: Fix typo: `dimentional` -> `dimensional`