  </emu-alg>
      <emu-note>
        <p>
          This method always throws, because in the absence of `valueOf()`, expressions with arithmetic operators such as `plainDate1 > plainDate2` would fall back to being equivalent to `plainDate1.toString() > plainDate2.toString()`.
          Lexicographical comparison of serialized strings might not seem obviously wrong, because the result would sometimes be correct.
          Implementations are encouraged to phrase the error message to point users to `Temporal