diff --git a/misc/worker_helper.py b/misc/worker_helper.py
index 379f3b3..2ecb30f 100644
--- a/misc/worker_helper.py
+++ b/misc/worker_helper.py
@@ -63,11 +63,12 @@ def walltime2seconds(walltime):
     220343
     '''
     time_strs = walltime.split(':')[::-1]
-    seconds = 0
-    for period, multiplier in zip(map(int, time_strs),
-                                 [1, 60, 3600, 24*3600]):
-        seconds += period*multiplier
-    return seconds
+    return sum(
+        period * multiplier
+        for period, multiplier in zip(
+            map(int, time_strs), [1, 60, 3600, 24 * 3600]
+        )
+    )
 
 
 # see derivation.ipynb for details on this function
diff --git a/tests/Reductor/counter.py b/tests/Reductor/counter.py
index 4cc0454..0113dfc 100755
--- a/tests/Reductor/counter.py
+++ b/tests/Reductor/counter.py
@@ -18,16 +18,16 @@
     arg_parser.add_argument('--verbose', action='store_true',
                             help='verbose output')
     options = arg_parser.parse_args()
-    count = dict()
+    count = {}
     with open(options.input, 'r') as in_file:
-        for line_nr in xrange(options.start):
+        for _ in xrange(options.start):
             _ = in_file.readline()
         for line_nr in xrange(options.start, options.end):
             line = in_file.readline().rstrip()
             if not line:
                 break
             if options.verbose:
-                sys.stderr.write('processing line ' + str(line_nr) + '\n')
+                sys.stderr.write(f'processing line {str(line_nr)}' + '\n')
             for word in line.split():
                 if word not in count:
                     count[word] = 0
diff --git a/tests/Reductor/data_generator.py b/tests/Reductor/data_generator.py
index 15baf49..cd4d29d 100755
--- a/tests/Reductor/data_generator.py
+++ b/tests/Reductor/data_generator.py
@@ -16,8 +16,6 @@
     for _ in xrange(options.lines):
         words = []
         for _ in xrange(options.words_per_line):
-            word = ''
-            for _ in xrange(options.word_length):
-                word += random.choice('ABCDE')
+            word = ''.join(random.choice('ABCDE') for _ in xrange(options.word_length))
             words.append(word)
         print(' '.join(words))
diff --git a/tests/Reductor/pickle_empty.py b/tests/Reductor/pickle_empty.py
index 4ec3ad4..de06f62 100755
--- a/tests/Reductor/pickle_empty.py
+++ b/tests/Reductor/pickle_empty.py
@@ -8,6 +8,6 @@
                                             'dictionary')
     arg_parser.add_argument('out', help='name of the pickle file')
     options = arg_parser.parse_args()
-    counter = dict()
+    counter = {}
     with open(options.out, 'wb') as out_file:
         pickle.dump(counter, out_file)