Comparing class with and without __slots__

slots.py

import numpy as np
import pandas as pd
import objgraph

### class without __slots__
class PointWithDict():
    def __init__(self, iters):
        self.iters = iters
    def convert(self):
        s = ["xyz"]*self.iters
        s = "".join(s)
        assert len(s) == 3*iters
        
w_dict = PointWithDict(10000)
objgraph.show_refs([w_dict], filename='PointWithDict_structure.png')

### class using __slots__
class PointWithSlots():
    __slots__ = "iters"
    def __init__(self, iters):
        self.iters = iters
    def convert(self):
        s = ["xyz"]*self.iters
        s = "".join(s)
        assert len(s) == 3*iters
        
w_slots = PointWithSlots(10000)
objgraph.show_refs([w_slots],filename='PointWithSlots_structure.png')

### Check memory footprint
>>> print(sys.getsizeof(w_dict), sys.getsizeof(w_dict.__weakref__), sys.getsizeof(w_dict.__dict__))
64 16 120
>>> print(sys.getsizeof(ob))
56

I think there is a typo on line 33. Guess it should be w_slots instead