code: def _denom(beta, log_f_by_k):
      s = (1.0 - beta) * log_f_by_k
      s_squared = s * s
      return 1.0 + s_squared / 24.0 + (s_squared * s_squared) / 1920.0
  
file_path: tf-quant-finance/tf_quant_finance/models/sabr/approximations/implied_volatility.py
imports: import enum
  import tensorflow.compat.v2
label_desc: Use image node_id 4 for calling a global function with example usage: _denom(beta, log_f_by_k) and returns: unknown