old_contents: class Color(object):
      def __init__(self, r, g, b):
          self.r = r
          self.g = g
          self.b = b
  
  
  class Line(object):
      def __init__(self, name, api_code, bg_color, fg_color):
          self.name = name
          self.api_code = api_code
          self.bg_color = bg_color
          self.fg_color = fg_color
  
      def __repr__(self):
          return self.name
      __unicode__ = __repr__
  
  
  class Station(object):
      def __init__(self, name, api_code):
          self.name = name
          self.api_code = api_code
  
          self.lines = []
          self.connections = {}
  
      def __repr__(self):
          return self.name
      __unicode__ = __repr__
  
  class Map(object):
      pass
  
new_contents: class Color(object):
      def __init__(self, r, g, b):
          self.r = r
          self.g = g
          self.b = b
  
  
  class Line(object):
      def __init__(self, name, api_code, bg_color, fg_color):
          self.name = name
          self.api_code = api_code
          self.bg_color = bg_color
          self.fg_color = fg_color
  
      def __repr__(self):
          return self.name
      __unicode__ = __repr__
  
  
  class Station(object):
      def __init__(self, name, api_code):
          self.name = name
          self.api_code = api_code
  
          self.connections = {}
  
      def __repr__(self):
          return self.name
      __unicode__ = __repr__
  
      @property
      def lines(self):
          return self.connections.keys()
  
  class Map(object):
      pass
  
subject: Make Station.lines into a property