code: def update(dst, src):
      
      for k, v in src.items():
          if isinstance(v, Mapping):
              r = update(dst.get(k, {}), v)
              dst[k] = r
          else:
              dst[k] = src[k]
      return dst
docs: Recursively update values in dst from src.
  
      Unlike the builtin dict.update() function, this method will decend into
      nested dicts, updating all nested values.
  
      Arguments:
          dst (dict): Destination dict.
          src (dict): Source dict.
  
      Returns:
          dict: dst updated with entries from src.