code: def __add__(self, val):
      if isinstance(val, AD):
          return AD(self.x + val.x, self.dx + val.dx)
      else:
          return AD(self.x + val, self.dx)
  
file_path: ppft/ppft/tests/auto_diff.py
imports: import math
  import sys
  import ppft
label_desc: Use image node_id 3 for calling the AD obj's underlying member method code with example usage: obj.__add__(val) and returns: AD, AD