onstructor:</p>
    <ul>
      <li>
        creates and initializes a new Temporal.PlainDate object when called as a constructor.
      </li>
      <li>
        is not intended to be called as a function and will throw an exception when called in that manner.
      </li>
      <li>
        may be used as the value of an `extends` clause of a class definition.
        Subclass constructors that intend to inherit the specified Temporal.PlainDate behaviour must
        include a super call to the %Temporal.Pla