Fix #13, PEP8-ify notebooks.

arrays_strings/permutation/test_permutation_solution.py

@@ -2,7 +2,7 @@ from nose.tools import assert_equal
 
 
 class TestPermutation(object):
-    
+
     def test_permutation(self, func):
         assert_equal(func('', 'foo'), False)
         assert_equal(func('Nib', 'bin'), False)
@@ -10,6 +10,7 @@ class TestPermutation(object):
         assert_equal(func('a ct', 'ca t'), True)
         print('Success: test_permutation')
 
+
 def main():
     test = TestPermutation()
     test.test_permutation(permutations)
@@ -19,6 +20,7 @@ def main():
         # Alternate solutions are only defined
         # in the solutions file
         pass
-    
+
+
 if __name__ == '__main__':
     main()