diff --git a/ch01python/101Classes.ipynb.py b/ch01python/101Classes.ipynb.py
index 32be9d51..53f2ee89 100644
--- a/ch01python/101Classes.ipynb.py
+++ b/ch01python/101Classes.ipynb.py
@@ -24,7 +24,7 @@
 # It can be defined like:
 
 # %%
-class Room(object):
+class Room:
     pass
 
 
diff --git a/ch02data/110Capstone.ipynb.py b/ch02data/110Capstone.ipynb.py
index fbe90f1f..74f041a1 100644
--- a/ch02data/110Capstone.ipynb.py
+++ b/ch02data/110Capstone.ipynb.py
@@ -44,7 +44,7 @@
 from .map import Map
 
 
-class Greengraph(object):
+class Greengraph:
     def __init__(self, start, end):
         self.start = start
         self.end = end
@@ -99,7 +99,7 @@ def plot_green_between(self, steps):
 # cells below might error out on the browser (jupyterlite) version of this notebook
 import requests
 
-class Map(object):
+class Map:
     def __init__(self, latitude, longitude, satellite=True, zoom=10,
                  sensor=False):
         base = "https://mt0.google.com/vt?"
diff --git a/ch03tests/08DiffusionExample.ipynb.py b/ch03tests/08DiffusionExample.ipynb.py
index 5626bc64..06567f83 100644
--- a/ch03tests/08DiffusionExample.ipynb.py
+++ b/ch03tests/08DiffusionExample.ipynb.py
@@ -69,7 +69,7 @@
 
 
 
-class MonteCarlo(object):
+class MonteCarlo:
     """ A simple Monte Carlo implementation """
 
     def __init__(self, energy, density, temperature=1, itermax=1000):
diff --git a/ch04packaging/025TextFiles.ipynb.py b/ch04packaging/025TextFiles.ipynb.py
index 745f896e..65191432 100644
--- a/ch04packaging/025TextFiles.ipynb.py
+++ b/ch04packaging/025TextFiles.ipynb.py
@@ -47,7 +47,7 @@
 from .room import Room
 from .person import Person
 
-class Maze(object):
+class Maze:
     def __init__(self, name):
         self.name = name
         self.rooms = []
@@ -92,7 +92,7 @@ def simulate(self, steps):
 from .exit import Exit
 
 
-class Room(object):
+class Room:
     def __init__(self, name, capacity):
         self.name = name
         self.capacity = capacity
@@ -119,7 +119,7 @@ def add_exit(self, name, target):
 # %%
 # %%writefile mazetool/person.py
 
-class Person(object):
+class Person:
     def __init__(self, name, room = None):
         self.name=name
         self.room=room
@@ -143,7 +143,7 @@ def describe(self):
 # %%
 # %%writefile mazetool/exit.py
 
-class Exit(object):
+class Exit:
     def __init__(self, name, target):
         self.name = name
         self.target = target
diff --git a/ch05construction/03comments.ipynb.py b/ch05construction/03comments.ipynb.py
index 4e7b29b9..5e7d9585 100644
--- a/ch05construction/03comments.ipynb.py
+++ b/ch05construction/03comments.ipynb.py
@@ -103,7 +103,7 @@ def move(self):
 
 # %%
 x.clear() # Code crashes here sometimes
-class Agent(object):
+class Agent:
     pass
     # TODO: Implement pretty-printer method
 
diff --git a/ch05construction/05refactoring.ipynb.py b/ch05construction/05refactoring.ipynb.py
index 051dda20..a3df02fa 100644
--- a/ch05construction/05refactoring.ipynb.py
+++ b/ch05construction/05refactoring.ipynb.py
@@ -388,7 +388,7 @@ def can_see(source, target):
 if hawk.can_see(starling):
     hawk.hunt(starling)
 
-class Hawk(object):
+class Hawk:
     def can_see(self, target):
         return (self.facing - target.facing) < viewport
 
@@ -407,7 +407,7 @@ def can_see(self, target):
 if hawk.can_see(starling, viewport):
     hawk.hunt(starling)
 
-class Hawk(object):
+class Hawk:
     def can_see(self, target, viewport):
         return (self.facing - target.facing) < viewport
 
@@ -508,10 +508,10 @@ def predate(predator, prey):
 #
 
 # %%
-class One(object):
+class One:
     pass
 
-class Two(object):
+class Two:
     def __init__():
         self.child = One()
 
@@ -527,14 +527,14 @@ def __init__():
 
 # %%
 # %%writefile anotherfile.py
-class One(object):
+class One:
     pass
 
 
 # %%
 from anotherfile import One
 
-class Two(object):
+class Two:
     def __init__():
         self.child = One()
 
diff --git a/ch05construction/06objects.ipynb.py b/ch05construction/06objects.ipynb.py
index f98d4f26..bd4d1987 100644
--- a/ch05construction/06objects.ipynb.py
+++ b/ch05construction/06objects.ipynb.py
@@ -307,7 +307,7 @@ def emigrate_probability(self): pass
 #
 
 # %%
-class Person(object):
+class Person:
     def __init__(self, birthday, name):
         self.birth_day = birthday[0]
         self.birth_month = birthday[1]
diff --git a/ch05construction/08objects.ipynb.py b/ch05construction/08objects.ipynb.py
index 200d37b2..9709f2d4 100644
--- a/ch05construction/08objects.ipynb.py
+++ b/ch05construction/08objects.ipynb.py
@@ -187,7 +187,7 @@ def __init__(self):
 #
 
 # %%
-class Person(object):
+class Person:
     def __init__(self):
         self._first = "Graham"
         self._second = "Chapman"
@@ -217,7 +217,7 @@ def name(self):
 #
 
 # %%
-class Person(object):
+class Person:
     def __init__(self):
         self._name = "Graham Chapman"
         
@@ -235,7 +235,7 @@ def name(self):  # an access function
 # Another way could be to create a member variable `name` which holds the full name. However, this could lead to inconsistent data. If we create a `get_married` function, then the name of the person won't change!
 
 # %%
-class Person(object):
+class Person:
     def __init__(self, first, second):
         self._first = first
         self._second = second
diff --git a/ch05construction/09patterns.ipynb.py b/ch05construction/09patterns.ipynb.py
index 1e4b1ae7..f5e026e2 100644
--- a/ch05construction/09patterns.ipynb.py
+++ b/ch05construction/09patterns.ipynb.py
@@ -265,7 +265,7 @@ def __init__(self, data):
 # Then, our analysis class which contains all methods *except* the numerical methods
 
 # %% pycharm={"name": "#%%\n"}
-class SunspotDataAnalyser(object):
+class SunspotDataAnalyser:
     def __init__(self, frequency_strategy):
         self.secs_per_year = (
                              datetime(2014, 1, 1) - datetime(2013, 1, 1)
diff --git a/ch05construction/species.py b/ch05construction/species.py
index 4a12d4cd..903c6a12 100644
--- a/ch05construction/species.py
+++ b/ch05construction/species.py
@@ -1,2 +1,2 @@
-class Species(object):
+class Species:
      pass
diff --git a/ch07dry/025Iterators.ipynb.py b/ch07dry/025Iterators.ipynb.py
index 26d7fae7..b2d9e49f 100644
--- a/ch07dry/025Iterators.ipynb.py
+++ b/ch07dry/025Iterators.ipynb.py
@@ -181,7 +181,7 @@ def __next__(self):
 from matplotlib import pyplot as plt
 
 
-class MyImage(object):
+class MyImage:
     def __init__(self, pixels):
         self.pixels = array(pixels, dtype='uint8')
         self.channels = self.pixels.shape[2]
diff --git a/ch07dry/049Operators.ipynb.py b/ch07dry/049Operators.ipynb.py
index 7988ba41..58a859dc 100644
--- a/ch07dry/049Operators.ipynb.py
+++ b/ch07dry/049Operators.ipynb.py
@@ -204,7 +204,7 @@ def __contains__(self, value):
 # one is `__call__`, which overrides the `()` operator; this allows us to define classes that *behave like functions*! We call these **callables**.
 
 # %%
-class Greeter(object):
+class Greeter:
     def __init__(self, greeting):
         self.greeting = greeting
         
diff --git a/ch98rubrics/Assessment1.md b/ch98rubrics/Assessment1.md
index a7c25d86..fd3cf67b 100644
--- a/ch98rubrics/Assessment1.md
+++ b/ch98rubrics/Assessment1.md
@@ -69,7 +69,7 @@ from StringIO import StringIO
 from matplotlib import image as img
 
 
-class Greengraph(object):
+class Greengraph:
     def __init__(self, start, end):
         self.start=start
         self.end=end
@@ -92,7 +92,7 @@ class Greengraph(object):
                     self.geolocate(self.end),
                     steps)]
 
-class Map(object):
+class Map:
     def __init__(self, lat, long, satellite=True,
            zoom=10, size=(400,400), sensor=False):
         base="http://maps.googleapis.com/maps/api/staticmap?"