text: from collections import Sequence
  
  class ReadOnlyList(Sequence):
      '''Don't forget the docstrings'''
  
      def __init__(self, *args, **kwargs):
          self._l = list(*args, **kwargs)
          self._index = -1
  
      def __contains__(self, key):
          return self._l.__contains__(key)
  
      def __getitem__(self, key):
          return self._l[key]
  
      def __iter__(self):
          return self
  
      def __len__(self):
          return len(self._l)
  
      def __next__(self):
          self._index += 1
          if self._index >= len(self):
              self._index = -1
              raise StopIteration
          return self._l[self._index]
  