diff --git a/cryptorandom/cryptorandom.py b/cryptorandom/cryptorandom.py
index 7404692..ab6388a 100644
--- a/cryptorandom/cryptorandom.py
+++ b/cryptorandom/cryptorandom.py
@@ -2,7 +2,6 @@
 SHA-256 PRNG prototype in Python
 """
 
-from __future__ import division
 import numpy as np
 import sys
 import struct
diff --git a/cryptorandom/prng.py b/cryptorandom/prng.py
index 4d11277..e38ca3b 100644
--- a/cryptorandom/prng.py
+++ b/cryptorandom/prng.py
@@ -1,4 +1,3 @@
-from __future__ import division
 import numpy as np
 
 # LCG; defaults to RANDU, a particularly bad choice
diff --git a/cryptorandom/sample.py b/cryptorandom/sample.py
index ac945bf..9c1848c 100644
--- a/cryptorandom/sample.py
+++ b/cryptorandom/sample.py
@@ -2,7 +2,6 @@
 Sampling with or without weights, with or without replacement.
 """
 
-from __future__ import division
 import numpy as np
 import math
 from .cryptorandom import SHA256
@@ -29,7 +28,7 @@ def get_prng(seed=None):
         return SHA256(seed)
     if hasattr(seed, "random") and hasattr(seed, "randint"):
         return seed
-    raise ValueError('%r cannot be used to seed a PRNG' % seed)
+    raise ValueError(f'{seed!r} cannot be used to seed a PRNG')
 
 
 def random_sample(a, size, replace=False, fast=False, p=None, method="sample_by_index", prng=None):
diff --git a/cryptorandom/tests/test_cryptorandom.py b/cryptorandom/tests/test_cryptorandom.py
index 49de4ff..d65d344 100644
--- a/cryptorandom/tests/test_cryptorandom.py
+++ b/cryptorandom/tests/test_cryptorandom.py
@@ -1,7 +1,5 @@
 """Unit tests for cryptorandom PRNG"""
 
-from __future__ import (absolute_import, division,
-                        print_function, unicode_literals)
 import numpy as np
 from ..cryptorandom import SHA256, int_from_hash
 
diff --git a/cryptorandom/tests/test_sample.py b/cryptorandom/tests/test_sample.py
index 7e78255..7ccce34 100644
--- a/cryptorandom/tests/test_sample.py
+++ b/cryptorandom/tests/test_sample.py
@@ -1,7 +1,5 @@
 """Unit tests for cryptorandom sampling functions."""
 
-from __future__ import (absolute_import, division,
-                        print_function, unicode_literals)
 import pytest
 import numpy as np
 from ..sample import *
diff --git a/doc/conf.py b/doc/conf.py
index 463a420..1044a65 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 #
 # cryptorandom documentation build configuration file, created by
 # sphinx-quickstart on Fri Oct 21 12:13:15 2016.
@@ -224,8 +223,8 @@
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
 latex_documents = [
-  (master_doc, 'cryptorandom.tex', u'cryptorandom Documentation',
-   u'Kellie Ottoboni and Philip B. Stark', 'manual'),
+  (master_doc, 'cryptorandom.tex', 'cryptorandom Documentation',
+   'Kellie Ottoboni and Philip B. Stark', 'manual'),
 ]
 
 # The name of an image file (relative to this directory) to place at the top of
@@ -254,7 +253,7 @@
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
 man_pages = [
-    (master_doc, 'cryptorandom', u'cryptorandom Documentation',
+    (master_doc, 'cryptorandom', 'cryptorandom Documentation',
      [author], 1)
 ]
 
@@ -268,7 +267,7 @@
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
 texinfo_documents = [
-  (master_doc, 'cryptorandom', u'cryptorandom Documentation',
+  (master_doc, 'cryptorandom', 'cryptorandom Documentation',
    author, 'cryptorandom', 'One line description of project.',
    'Miscellaneous'),
 ]
diff --git a/setup.py b/setup.py
index 311ab48..74106a4 100755
--- a/setup.py
+++ b/setup.py
@@ -25,7 +25,7 @@
             VERSION = line.strip().split()[-1][1:-1]
             break
 
-with open("README.md", "r") as fh:
+with open("README.md") as fh:
     LONG_DESCRIPTION = fh.read()
 
 def parse_requirements_file(filename):