code: def as_list(self):
          
          if self._dims is None:
              raise ValueError("as_list() is not defined on an unknown TensorShape.")
          return [dim.value for dim in self._dims]
docs: Returns a list of integers or `None` for each dimension.
  
          Returns:
            A list of integers or `None` for each dimension.
  
          Raises:
            ValueError: If `self` is an unknown shape with an unknown rank.