code: def is_equiv(self, str1, str2, verbose=False):
      if str1 is None and str2 is None:
          print("WARNING: Both None")
          return True
      if str1 is None or str2 is None:
          return False
  
      try:
          ss1 = self.strip_string(str1)
          ss2 = self.strip_string(str2)
          if verbose:
              print(ss1, ss2)
          return ss1 == ss2
      except Exception:
          return str1 == str2
  
imports: import inspect
  import lm_eval.datasets.hendrycks_math.hendrycks_math
  from lm_eval.metrics import mean
  from lm_eval.base import Task, rf
label_desc: Use image node_id 16 for calling the Math obj's underlying member method code with example usage: obj.is_equiv(str1, str2, verbose) and returns: True, False, unknown, unknown