code: def _accumulate_props(dest_props, src_props):
      
      props_size = 0
      if src_props:
          for k, v in src_props.items():
              if v is not None:
                  props_size += len(k) + _sizeof(v)
                  dest_props[k] = v
      return props_size
docs: helper to accumulate a dict of properties
  
      Mutates dest_props by adding the non None src_props and returns
      the new size