old_contents: from city_element import CityElement
  import random
  
  
  # City models correspond to Gazebo models, and hence need a name
  class CityModel(CityElement):
  
      incrementing_id = 0
  
      def __init__(self, name=None):
          super(CityModel, self).__init__()
          if name is None:
              class_name = self.__class__.__name__
              CityModel.incrementing_id += 1
              self.name = (class_name[0].lower()
                           + class_name[1:]
                           + '_'
                           + str(CityModel.incrementing_id))
          else:
              self.name = name
  
      def material(self):
          colors = ['Red', 'Blue', 'White', 'Yellow', 'Green', 'Black', 'Purple']
          return """<script>
            <uri>
              file://media/materials/scripts/gazebo.material
            </uri>
            <name>Gazebo/{0}</name>
          </script>""".format(random.choice(colors))
  
new_contents: from city_element import CityElement
  import random
  
  
  # City models correspond to Gazebo models, and hence need a name
  class CityModel(CityElement):
  
      incrementing_id = 0
  
      def __init__(self, name=None):
          super(CityModel, self).__init__()
          if name is None:
              class_name = self.__class__.__name__
              CityModel.incrementing_id += 1
              self.name = (class_name[0].lower()
                           + class_name[1:]
                           + '_'
                           + str(CityModel.incrementing_id))
          else:
              self.name = name
  
      def material(self):
          return """<script>
            <uri>
              file://media/materials/scripts/gazebo.material
            </uri>
            <name>Gazebo/Grey</name>
          </script>"""
  
      def _material_with_random_color(self):
          """This is mostly for debugging / visualization purposes. Do not rely
          on the existence of this method, we will eventually remove it"""
          colors = ['Red', 'Blue', 'White', 'Yellow', 'Green', 'Black', 'Purple']
          return """<script>
            <uri>
              file://media/materials/scripts/gazebo.material
            </uri>
            <name>Gazebo/{0}</name>
          </script>""".format(random.choice(colors))
  
subject: Fix debugging code