Compare object sizes in python 3.6

test.py

import attr
from pympler import asizeof

@attr.s()
class Coordinates():
   x = attr.ib()
   y = attr.ib()

c = Coordinates(x=1, y=2)

@attr.s(slots=True)
class CoordinatesSlots():
   x = attr.ib()
   y = attr.ib()

a = Coordinates(x=1, y=2)
b = CoordinatesSlots(x=1, y=2)

print('No slot: ', asizeof.asizeof(a))
print('With slot: ', asizeof.asizeof(b))

$ py test.py
No slot:  344
With slot:  128