def _merge_config_dicts(dct1, dct2):
    """
    Return new dict created by merging two dicts, giving dct1 priority over
    dct2, but giving truthy values in dct2 priority over falsey values in dct1.
    """
    return {str(key): dct1.get(key) or dct2.get(key)
            for key in set(dct1) | set(dct2)}