def _merge_nested(a, b):
        """
        merges b into a
        leaf values in a are overwritten with values from b
        """
        for key in b:
            if key in a:
                if isinstance(a[key], dict) and isinstance(b[key], dict):
                    ChromeOptions._merge_nested(a[key], b[key])
                    continue
            a[key] = b[key]
        return a

        merges b into a
        leaf values in a are overwritten with values from b
        
src/undetected_chromedriver/options.py