code: def log_sum_exp(a: float, b: float):
      if a == global_constants.FP32_NEG_INF:
          return b
  
      if b == global_constants.FP32_NEG_INF:
          return a
  
      if a > b:
          return math.log1p(math.exp(b - a)) + a
      else:
          return math.log1p(math.exp(a - b)) + b
  
file_path: espnet/espnet2/asr/transducer/rnnt_multi_blank/utils/rnnt_helper.py
imports: import math
  from typing import Optional, Tuple
  import torch
  from numba import cuda
  from espnet2.asr.transducer.rnnt_multi_blank.utils import global_constants
label_desc: Use image node_id 1 for calling a global function with example usage: log_sum_exp(a, b) and returns: b, a, unknown, unknown