code: def compile(expression, escape_funcs=None, unescape_funcs=None):
      
      return _compile_from_parse_tree(
          parse_regex(tokenize_regex(expression)),
          escape_funcs=escape_funcs,
          unescape_funcs=unescape_funcs)
docs: Compile grammar (given as regex string), returning a `CompiledGrammar`
      instance.