code: function print(node, showPlusMinus=false) {
    let string = printTreeTraversal(node);
    if (!showPlusMinus) {
      string = string.replace(/\s*?\+\s*?\-\s*?/g, ' - ');
    }
    return string;
  }
docs: Prints an expression node in asciimath If showPlusMinus is true, print + - (e.g. 2 + -3) If it's false (the default) 2 + -3 would print as 2 - 3 (The + - is needed to support the conversion of subtraction to addition of negative terms. See flattenOperands for more details if you're curious.)