code: def is_contiguous(self):
          '''Return whether entire collection is contiguous.'''
          previous = None
          for index in self.indexes:
              if previous is None:
                  previous = index
                  continue
  
              if index != (previous + 1):
                  return False
  
              previous = index
  
          return Truf is_contiguous(self):
          '''Return whether entire collection is contiguous.'''
          previous = None
          for index in self.indexes:
              if previous is None:
                  previous = index
                  continue
  
              if index != (previous + 1):
                  return False
  
              previous = index
  
          return True
docs: Return whether entire collection is contiguous.