removes six dependency

tests/test_utils.py

@@ -5,7 +5,7 @@
 from __future__ import (absolute_import, division, print_function, unicode_literals)
 import numpy as np
 from descent.utils import destruct, restruct, lrucache, check_grad
-from six import StringIO
+from io import StringIO
 from time import sleep, time
 
 
@@ -42,17 +42,16 @@ def test_check_grad():
     """Tests the check_grad() function"""
 
     def f_df_correct(x):
-        return x**2, 2*x
+        return x**2, 2 * x
 
     def f_df_incorrect(x):
-        return x**3, 0.5*x**2
+        return x**3, 0.5 * x**2
 
     output = StringIO()
     check_grad(f_df_correct, 5, out=output)
 
     # helper functions
-    getvalues = lambda o: [float(s.strip()) for s in \
-                           o.getvalue().split('\n')[3].split('|')[:-1]]
+    getvalues = lambda o: [float(s.strip()) for s in o.getvalue().split('\n')[3].split('|')[:-1]]
 
     # get the first row of data
     values = getvalues(output)
@@ -63,8 +62,7 @@ def f_df_incorrect(x):
     check_grad(f_df_incorrect, 5, out=output)
     values = getvalues(output)
     printed_error = values[2]
-    correct_error = np.abs(values[0] - values[1]) \
-                    / (np.abs(values[0]) + np.abs(values[1]))
+    correct_error = np.abs(values[0] - values[1]) / (np.abs(values[0]) + np.abs(values[1]))
     assert np.isclose(printed_error, correct_error), "Correct relative error"
 
 
@@ -97,18 +95,19 @@ def test_destruct():
     assert np.allclose(larray, destruct(tuple(lref))), "Tuple destruct"
 
     # Composed / mixed types
-    lref = [np.eye(2), {'a': np.array([-1,1]), 'b': np.arange(3)}, 7]
+    lref = [np.eye(2), {'a': np.array([-1, 1]), 'b': np.arange(3)}, 7]
     larray = np.array([1, 0, 0, 1, -1, 1, 0, 1, 2, 7])
     assert np.allclose(larray, destruct(lref)), "List of mixed types"
 
     dref = {
         'a': [3.5, 1.2, -33],
-        'b': np.arange(6).reshape(2,3),
+        'b': np.arange(6).reshape(2, 3),
         'c': 7
     }
     darray = np.array([3.5, 1.2, -33, 0, 1, 2, 3, 4, 5, 7])
     assert np.allclose(darray, destruct(dref)), "Dictionary of mixed types"
 
+
 def test_restruct():
     """Tests the destruct utility function"""
 
@@ -148,19 +147,19 @@ def test_restruct():
         assert np.allclose(lref[idx], val), "Tuple restruct"
 
     # Composed / mixed types
-    lref = [np.eye(2), {'a': np.array([-1,1]), 'b': np.arange(3)}, 7]
-    lzeros = [np.zeros((2,2)), {'a': np.zeros(2), 'b': np.zeros(3)}, 0]
+    lref = [np.eye(2), {'a': np.array([-1, 1]), 'b': np.arange(3)}, 7]
+    lzeros = [np.zeros((2, 2)), {'a': np.zeros(2), 'b': np.zeros(3)}, 0]
     larray = np.array([1, 0, 0, 1, -1, 1, 0, 1, 2, 7])
     assert np.allclose(destruct(restruct(larray, lzeros)), destruct(lref)), "List of mixed types"
 
     dref = {
         'a': [3.5, 1.2, -33],
-        'b': np.arange(6).reshape(2,3),
+        'b': np.arange(6).reshape(2, 3),
         'c': 7
     }
     dzeros = {
         'a': [0, 0, 0],
-        'b': np.zeros((2,3)),
+        'b': np.zeros((2, 3)),
         'c': 0
     }
     darray = np.array([3.5, 1.2, -33, 0, 1, 2, 3, 4, 5, 7])