class_docstr: Mocks the `open` built-in function. A call to the instance of OpenMock returns an in-memory file which is
  readable and writable. The actual in-memory file implementation should call the passed `save_value` method
  to save the file content in the cache when the file is being closed to preserve the file content.
code: def save_value(self, value, file):
      self.values[file] = value
  
imports: import inspect
  import random
  import typing
  from io import StringIO
  from typing import Optional, Set, Type
  import numpy
  import albumentations
label_desc: Use image node_id 3 for calling the OpenMock obj's underlying member method code with example usage: obj.save_value(value, file) without return types