text: """
  MapLayer class for storing class layers.
  """
  
  class MapLayer:
  
      def __init__(self, layer: list, is_solid: bool=None):
          self.layer = tuple(tuple(row) for row in layer)
          self.is_solid = False if is_solid is None else is_solid
  
      def __getitem__(self, key: int):
          return self.layer[key]
  
      def __iter__(self):
          return self.layer.__iter__()
  
      def __len__(self):
          return len(self.layer)
  
      def __str__(self):
          return ('*' if self.is_solid else '') + str(self.layer)
  