class_docstr: Stores some state that persists between recursions into the element tree
docstr: Generate a number used in the name of an otherwise unnamed diagram
code: def generate_unnamed(self) -> int:
      """
      Generate a number used in the name of an otherwise unnamed diagram
      """
      self.unnamed_index += 1
      return self.unnamed_index
  
imports: import railroad
  import pyparsing
  import typing
  from typing import List, NamedTuple, Generic, TypeVar, Dict, Callable, Set, Iterable
  from jinja2 import Template
  from io import StringIO
  import inspect
label_desc: Use image node_id 6 for calling the ConverterState obj's underlying member method code with example usage: obj.generate_unnamed() and returns: self