code: def test_ur_literals():
      """
      Decided to parse `u''` literals regardless of Python version. This makes
      probably sense:
  
      - Python 3+ doesn't support it, but it doesn't hurt
        not be. While this is incorrect, it's just incorrect for one "old" and in
        the future not very important version.
      - All the other Python versions work very well with it.
      """
  
      def check(literal, is_literal=True):
          token_list = _get_token_list(literal)
          typ, result_literal, _, _ = token_list[0]
          if is_literal:
              if typ != FSTRING_START:
                  assert typ == STRING
                  assert result_literal == literal
          else:
              assert typ == NAME
  
      check('u""')
      check('ur""', is_literal=not sys.version_info.major >= 3)
      check('Ur""', is_literal=not sys.version_info.major >= 3)
      check('UR""', is_literal=not sys.version_info.major >= 3)
      check('bR""')
      # Starting with Python 3.3 this ordering is also possible.
      if sys.version_info.major >= 3:
          check('Rb""')
  
      # Starting with Python 3.6 format strings where introduced.
      check('fr""', is_literal=sys.version_info >= (3, 6))
      check('rF""', is_literal=sys.version_info >= (3, 6))
      check('f""', is_literal=sys.version_info >= (3, 6))
      check('F""', is_literal=sys.version_info >= (3, 6))
  
imports: import sys
  from textwrap import dedent
  import pytest
  from parso.utils import split_lines, parse_version_string
  from parso.python.token import PythonTokenTypes
  from parso.python import tokenize
  from parso import parse
  from parso.python.tokenize import PythonToken
label_desc: Use image node_id 12 for calling a global function with example usage: test_ur_literals() without return types