Remove TensorFlow Privacy dependency on six.

Python 2 is not supported, please use Python 3.

PiperOrigin-RevId: 424435761

tensorflow_privacy/privacy/analysis/rdp_accountant.py

@@ -42,9 +42,9 @@ from __future__ import print_function
 
 import math
 import sys
+
 import numpy as np
 from scipy import special
-import six
 
 ########################
 # LOG-SPACE ARITHMETIC #
@@ -106,7 +106,7 @@ def _log_comb(n, k):
 
 def _compute_log_a_int(q, sigma, alpha):
   """Compute log(A_alpha) for integer alpha. 0 < q < 1."""
-  assert isinstance(alpha, six.integer_types)
+  assert isinstance(alpha, int)
 
   # Initialize with 0 in the log space.
   log_a = -np.inf
@@ -486,7 +486,7 @@ def _compute_rdp_sample_without_replacement_int(q, sigma, alpha):
   """
 
   max_alpha = 256
-  assert isinstance(alpha, six.integer_types)
+  assert isinstance(alpha, int)
 
   if np.isinf(alpha):
     return np.inf

tensorflow_privacy/privacy/analysis/rdp_privacy_accountant.py

@@ -19,7 +19,7 @@ from typing import Collection, Optional
 
 import numpy as np
 from scipy import special
-import six
+
 from tensorflow_privacy.privacy.analysis import dp_event
 from tensorflow_privacy.privacy.analysis import privacy_accountant
 
@@ -74,7 +74,7 @@ def _log_comb(n, k):
 
 def _compute_log_a_int(q, sigma, alpha):
   """Computes log(A_alpha) for integer alpha, 0 < q < 1."""
-  assert isinstance(alpha, six.integer_types)
+  assert isinstance(alpha, int)
 
   # Initialize with 0 in the log space.
   log_a = -np.inf
@@ -430,7 +430,7 @@ def _compute_rdp_sample_wor_gaussian_int(q, sigma, alpha):
   """
 
   max_alpha = 256
-  assert isinstance(alpha, six.integer_types)
+  assert isinstance(alpha, int)
 
   if np.isinf(alpha):
     return np.inf

tensorflow_privacy/privacy/dp_query/gaussian_query_test.py

@@ -19,7 +19,6 @@ from __future__ import print_function
 
 from absl.testing import parameterized
 import numpy as np
-from six.moves import xrange
 import tensorflow.compat.v1 as tf
 
 from tensorflow_privacy.privacy.dp_query import gaussian_query
@@ -81,7 +80,7 @@ class GaussianQueryTest(tf.test.TestCase, parameterized.TestCase):
       query_result, _ = test_utils.run_query(query, [record1, record2])
 
       noised_sums = []
-      for _ in xrange(1000):
+      for _ in range(1000):
         noised_sums.append(sess.run(query_result))
 
       result_stddev = np.std(noised_sums)

tensorflow_privacy/privacy/optimizers/dp_optimizer_eager_test.py

@@ -19,7 +19,6 @@ from __future__ import print_function
 
 from absl.testing import parameterized
 import numpy as np
-from six.moves import range
 import tensorflow.compat.v1 as tf
 
 from tensorflow_privacy.privacy.dp_query import gaussian_query

tensorflow_privacy/privacy/optimizers/dp_optimizer_test.py

@@ -18,10 +18,10 @@ from __future__ import division
 from __future__ import print_function
 
 import os
+
 from absl.testing import parameterized
 import mock
 import numpy as np
-from six.moves import range
 import tensorflow.compat.v1 as tf
 
 from tensorflow_privacy.privacy.dp_query import gaussian_query

tensorflow_privacy/privacy/optimizers/dp_optimizer_vectorized_test.py

@@ -20,7 +20,6 @@ from __future__ import print_function
 from absl.testing import parameterized
 import mock
 import numpy as np
-from six.moves import range
 import tensorflow.compat.v1 as tf
 
 from tensorflow_privacy.privacy.optimizers import dp_optimizer_vectorized