docs: def cmpabs(op1, op2):
      """
      Compare the absolute values of op1 and op2.
  
      Return a positive value if op1 > op2, zero if op1 = op2, and a negative
      value if op1 < op2. Both op1 and op2 are considered to their full own
      precision, which may differ. If one of the operands is NaN, raise
      ValueError.
  
      Note: This function may be useful to distinguish the three possible
      cases. If you need to distinguish two cases only, it is recommended to use
      the predicate functions like 'greaterequal'; they behave like the IEEE 754
      comparisons, in particular when one or both arguments are NaN.
  
      """
      op1 = BigFloat._implicit_convert(op1)
      op2 = BigFloat._implicit_convert(op2)
      if is_nan(op1) or is_nan(op2):
          raise ValueError("Cannot perform comparison with NaN.")
      return mpfr.mpfr_cmpabs(op1, op2)