class_docstr: Create an optional node. If this nodes evaluates to true, then the document
  will be rated higher in score/rank.
class_docstr_tok: ["Create","an","optional","node",".","If","this","nodes","evaluates","to","true",",","then","the","document","will","be","rated","higher","in","score\/rank","."]
code: def to_string(self, with_parens=None):
      with_parens = self._should_use_paren(with_parens)
      ret = super().to_string(with_parens=False)
      if with_parens:
          return "(~" + ret + ")"
      else:
          return "~" + ret
  
label_desc: Use image node_id 1 for calling the OptionalNode obj's underlying member method code with example usage: obj.to_string(with_parens) and returns: unknown, unknown