code: def get_metadata_value(self, key: str) -> typing.Any:
          
          return self._data_item.get_metadata_value(key)
docs: Get the metadata value for the given key.
  
          There are a set of predefined keys that, when used, will be type checked and be interoperable with other
          applications. Please consult reference documentation for valid keys.
  
          If using a custom key, we recommend structuring your keys in the '<group>.<attribute>' format followed
          by the predefined keys. e.g. 'session.instrument' or 'camera.binning'.
  
          Also note that some predefined keys map to the metadata ``dict`` but others do not. For this reason, prefer
          using the ``metadata_value`` methods over directly accessing ``metadata``.
  
          .. versionadded:: 1.0
  
          Scriptable: Yes