def METHOD_NAME(self) -> List[str]:
    """
    Returns the gcc command that will output the include hierarchy.
    :return: List of strings ready to be used in a subprocess.call.
    """
    tmp = self.command.split()
    tmp.insert(1, "-E")    # gcc postprocessing option to stop after preprocessing.
    tmp.insert(1, "-H")    # gcc postprocessing option to get the included headers
    return tmp