code: def LR_calc(item1, item2):
      """
      Calculate Likelihood ratio (LR).
  
      :param item1: item1 in expression
      :type item1:float
      :param item2: item2 in expression
      :type item2:float
      :return: LR+ and LR- as float
      """
      try:
          result = item1 / item2
          return result
      except (ZeroDivisionError, TypeError):
          return "None"
  
imports: from __future__ import division
  import math
  from .pycm_util import normal_quantile
  from .pycm_interpret import *
  from .pycm_param import CLASS_PARAMS
label_desc: Use image node_id 16 for calling a global function with example usage: LR_calc(item1, item2) and returns: result, str