def _is_chinese_char(char_code: int):
    """Checks whether char_code is the code of a Chinese character."""
    # https://en.wikipedia.org/wiki/List_of_CJK_Unified_Ideographs,_part_1_of_4
    if (
        (char_code >= 0x4E00 and char_code <= 0x9FFF)  # CJK Unified Ideographs
        or (char_code >= 0x3400 and char_code <= 0x4DBF)  # CJK Unified Ideographs Extension A
        or (char_code >= 0x20000 and char_code <= 0x2A6DF)  # CJK Unified Ideographs Extension B
        or (char_code >= 0x2A700 and char_code <= 0x2B73F)  # CJK Unified Ideographs Extension C
        or (char_code >= 0x2B740 and char_code <= 0x2B81F)  # CJK Unified Ideographs Extension D
        or (char_code >= 0x2B820 and char_code <= 0x2CEAF)  # CJK Unified Ideographs Extension E
        or (char_code >= 0xF900 and char_code <= 0xFAFF)  # CJK Compatibility Ideographs
        or (char_code >= 0x2F800 and char_code <= 0x2FA1F)  # CJK Compatibility Ideographs Supplement
    ):
        return True

    return False