code: function simplifySigns(fraction) {
    if (!Node.Type.isOperator(fraction) || fraction.op !== '/') {
      return Node.Status.noChange(fraction);
    }
    const oldFraction = clone(fraction);
    let numerator = fraction.args[0];
    let denominator = fraction.args[1];
    // The denominator should never be negative.
    if (Negative.isNegative(denominator)) {
      denominator = Negative.negate(denominator);
      const changeType = Negative.isNegative(numerator) ?
        ChangeTypes.CANCEL_MINUSES :
        ChangeTypes.SIMPLIFY_SIGNS;
      numerator = Negative.negate(numerator);
      const newFraction = Node.Creator.operator('/', [numerator, denominator]);
      return Node.Status.nodeChanged(changeType, oldFraction, newFraction);
    }
    else {
      return Node.Status.noChange(fraction);
    }
  }
docs: Simplifies negative signs if possible e.g. -1/-3 --> 1/3   4/-5 --> -4/5 Note that -4/5 doesn't need to be simplified. Note that our goal is for the denominator to always be positive. If it isn't, we can simplify signs. Returns a Node.Status object