code: def peek(self, ty=None, val=None):
      if self:
          token = self.tokens[self.idx]
          if check_type(token, ty, val):
              return token
  
      return None
  
imports: import re
  from dataclasses import dataclass, InitVar, field
  from itertools import chain
  from typing import Any, Dict, List, Union, Optional, ClassVar
  import numpy
  from toolz import valfilter, valmap
label_desc: Use image node_id 4 for calling the TokenStream obj's underlying member method code with example usage: obj.peek(ty, val) and returns: None, token