class_docstr: Configuration class.
  
  This class is responsible for loading, saving, and storing PennyLane
  and plugin/device configurations.
  
  Args:
      name (str): filename of the configuration file.
          This should be a valid TOML file. You may also pass an absolute
          or a relative file path to the configuration file.
code: def __getitem__(self, key):
      keys = key.split(".")
      return self.safe_get(self._config, *keys)
  
file_path: pennylane/pennylane/configuration.py
imports: import contextlib
  import os
  import toml
  from appdirs import user_config_dir
label_desc: Use image node_id 7 for calling the Configuration obj's underlying member method code with example usage: obj.__getitem__(key) and returns: self