def is_submodule_included(src, tgt):
    """Check that the tgt's submodule is included by src, if they belong
    to the same module."""
    if tgt is None or not hasattr(tgt, 'i_orig_module'):
        return True
    if (tgt.i_orig_module.keyword == 'submodule' and src.i_orig_module !=
        tgt.i_orig_module and src.i_orig_module.i_modulename == tgt.
        i_orig_module.i_modulename):
        if (src.i_orig_module.keyword == 'submodule' and src.i_orig_module.
            i_version != '1'):
            return True
        if src.i_orig_module.search_one('include', tgt.i_orig_module.arg
            ) is None:
            return False
    return True
