code: def calcu_max_tokens(self):
      tokens = 0
      for req in self.reqs:
          tokens += req.input_len + req.max_output_len
      return tokens
  
imports: from typing import Dict, List, Tuple
  from .sampling_params import SamplingParams
label_desc: Use image node_id 3 for calling the Batch obj's underlying member method code with example usage: obj.calcu_max_tokens() and returns: tokens