code: def GetMetadata(
        self, metadata_key='', recursive=True, timeout=None, retry=True):
      
      return self._HandleMetadataUpdate(
          metadata_key=metadata_key, recursive=recursive, wait=False,
          timeout=timeout, retry=retry)
docs: Retrieve the contents of metadata server for a metadata key.
  
      Args:
        metadata_key: string, the metadata key to watch for changes.
        recursive: bool, True if we should recursively watch for metadata changes.
        timeout: int, timeout in seconds for returning metadata output.
        retry: bool, True if we should retry on failure.
  
      Returns:
        json, the deserialized contents of the metadata server or None if error.