code: def to_text(self, form_manager):
      r_list = []
      for i in range(self.num_children):
          if isinstance(self.children[i], Tree):
              r_list.append(
                  "( " + self.children[i].to_text(form_manager) + " )"
              )
          else:
              r_list.append(
                  " "
                  + form_manager.get_idx_symbol(self.children[i])
                  + " "
              )
      return "".join(r_list)
  
imports: from operator import itemgetter
  import numpy
label_desc: Use image node_id 5 for calling the Tree obj's underlying member method code with example usage: obj.to_text(form_manager) and returns: str