new_contents: """This module contains classes for storing Stage information to be used
  by the game engine.
  
  Note that all classes in this module are read-only and should not have
  their data modified after being instantiated.
  """
  
  
  class StageData(object):
      """A data class that stores all of the required information about
      a battle stage.
  
      This data is retrieved from external XML files, which are read via
      functions within the stage_loader module.
  
      Attributes:
          name (String): The name of the Stage.
          subtitle (String): A tagline that appears below the Stage name
              in the Stage Select Screen.
          background (String): The file path to the backdrop image for
              this Stage.
          parallax (String): An optional file path that specifies another
              image drawn beneath the background. Unlike the latter, it
              will not be scrolled in order to give the scene a "layered"
              visual effect.
          x_offset (int): The horizontal displacement of the top-left
              corner of the screen relative to the background when the
              match starts.
          ground_level (int): The row of pixels on the background that
              specify where the characters' feet will touch while
              grounded.
          music (String): The file path to the audio file that will play
              as music while battling on this Stage.
      """
      def __init__(self):
          """Declare and initialize instance variables."""
          self.name = ''
          self.subtitle = ''
          self.background = ''
          self.parallax = ''
          self.x_offset = 0
          self.ground_level = 0
          self.music = ''
  
subject: Write the StageData class