class_docstr: This is very similar to ``torch.Size``, but carries a symbolic expression.
  
  The shape behaves like a tuple, and it can't inherit tuple.
  Otherwise it would be flattened when passed to :func:`_assign_shape_info`.
class_docstr_tok: ["This","is","very","similar","to","``","torch.Size","``",",","but","carries","a","symbolic","expression",".","The","shape","behaves","like","a","tuple",",","and","it","ca","n't","inherit","tuple",".","Otherwise","it","would","be","flattened","when","passed","to",":","func",":","`","_assign_shape_info","`","."]
code: def __getitem__(self, index):
      if isinstance(index, slice):
          return MutableShape(self._shape[index])
      else:
          return self._shape[index]
  
imports: from __future__ import annotations
  import functools
  import logging
  import traceback
  from typing import Union, Tuple, Callable, Iterable, Any, NamedTuple, Dict, cast, overload
  import torch
  from torch import nn
  from torch.utils.hooks import RemovableHandle
  from nni.mutable import MutableExpression, Mutable, LabeledMutable, Sample, SampleValidationError
  from nni.mutable.mutable import _mutable_equal
  from .misc import is_leaf_module, argument_in_spec
label_desc: Use image node_id 9 for calling the MutableShape obj's underlying member method code with example usage: obj.__getitem__(index) and returns: MutableShape, self