Get the numeric project ID for this VM.

    Returns:
      string, the numeric project ID if one is found.

def _GetNumericProjectId(self):
    """Get the numeric project ID for this VM.

    Returns:
      string, the numeric project ID if one is found.
    """
    project_id = 'project/numeric-project-id'
    return self.watcher.GetMetadata(metadata_key=project_id, recursive=False)