diff --git a/doc/contributing/pickle-to-xml.py b/doc/contributing/pickle-to-xml.py
index b2db082ad..6a4fcebb3 100755
--- a/doc/contributing/pickle-to-xml.py
+++ b/doc/contributing/pickle-to-xml.py
@@ -33,7 +33,6 @@ def dump_pickles(out, dirname, filename, path):
         next_path = os.path.normpath(os.path.join(path, data['next']['link']))
         next_filename = os.path.basename(next_path) + '.fpickle'
         dump_pickles(out, dirname, next_filename, next_path)
-    return
 
 import sys
 
diff --git a/doc/tutorial/pickle-to-xml.py b/doc/tutorial/pickle-to-xml.py
index b2db082ad..6a4fcebb3 100755
--- a/doc/tutorial/pickle-to-xml.py
+++ b/doc/tutorial/pickle-to-xml.py
@@ -33,7 +33,6 @@ def dump_pickles(out, dirname, filename, path):
         next_path = os.path.normpath(os.path.join(path, data['next']['link']))
         next_filename = os.path.basename(next_path) + '.fpickle'
         dump_pickles(out, dirname, next_filename, next_path)
-    return
 
 import sys
 
diff --git a/test.py b/test.py
index 336fd8ab5..87e5c6b67 100755
--- a/test.py
+++ b/test.py
@@ -22,7 +22,6 @@ import argparse
 import subprocess
 import threading
 import signal
-import xml.dom.minidom
 import shutil
 import fnmatch
 
@@ -32,14 +31,14 @@ from utils import get_list_from_file
 colors_lst={'USE':True,'BOLD':'\x1b[01;1m','RED':'\x1b[01;31m','GREEN':'\x1b[32m','YELLOW':'\x1b[33m','PINK':'\x1b[35m','BLUE':'\x1b[01;34m','CYAN':'\x1b[36m','GREY':'\x1b[37m','NORMAL':'\x1b[0m','cursor_on':'\x1b[?25h','cursor_off':'\x1b[?25l',}
 def get_color(cl):
     if colors_lst['USE']:
-        return colors_lst.get(cl,'')
-    return''
+        return colors_lst.get(cl, '')
+    return ''
 class color_dict(object):
-    def __getattr__(self,a):
+    def __getattr__(self, a):
         return get_color(a)
-    def __call__(self,a):
+    def __call__(self, a):
         return get_color(a)
-colors=color_dict()
+colors = color_dict()
 
 try:
     import queue
@@ -1246,13 +1245,13 @@ def run_tests():
             examples_sorted.sort()
         if ENABLE_PYTHON_BINDINGS:
             python_examples_sorted = []
-            for (x,y) in python_tests:
+            for (x, y) in python_tests:
                 if y == 'True':
                     python_examples_sorted.append(x)
             python_examples_sorted.sort()
             examples_sorted.extend(python_examples_sorted)
         for item in examples_sorted:
-                print("example     ", item)
+            print("example     ", item)
         print()
 
     if args.kinds or args.list:
@@ -1284,7 +1283,7 @@ def run_tests():
     if not os.path.exists(TMP_OUTPUT_DIR):
         os.makedirs(TMP_OUTPUT_DIR)
 
-    testpy_output_dir = os.path.join(TMP_OUTPUT_DIR, date_and_time);
+    testpy_output_dir = os.path.join(TMP_OUTPUT_DIR, date_and_time)
 
     if not os.path.exists(testpy_output_dir):
         os.makedirs(testpy_output_dir)
@@ -1390,7 +1389,7 @@ def run_tests():
     output_queue = queue.Queue(0)
 
     jobs = 0
-    threads=[]
+    threads = []
 
     #
     # In Python 2.6 you can just use multiprocessing module, but we don't want
@@ -1399,7 +1398,7 @@ def run_tests():
     processors = 1
 
     if sys.platform != "win32":
-        if 'SC_NPROCESSORS_ONLN'in os.sysconf_names:
+        if 'SC_NPROCESSORS_ONLN' in os.sysconf_names:
             processors = os.sysconf('SC_NPROCESSORS_ONLN')
         else:
             proc = subprocess.Popen("sysctl -n hw.ncpu", shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
@@ -1553,7 +1552,7 @@ def run_tests():
 
         key_list = []
         for key in ns3_runnable_programs_dictionary:
-            key_list.append (key)
+            key_list.append(key)
         example_name_key_list = fnmatch.filter(key_list, example_name)
 
         if len(example_name_key_list) == 0:
@@ -2013,7 +2012,7 @@ def main(argv):
     signal.signal(signal.SIGINT, sigint_hook)
 
     # From waf/waflib/Options.py
-    envcolor=os.environ.get('NOCOLOR','') and 'no' or 'auto' or 'yes'
+    envcolor = os.environ.get('NOCOLOR', '') and 'no' or 'auto' or 'yes'
 
     if args.nocolor or envcolor == 'no':
         colors_lst['USE'] = False
diff --git a/utils.py b/utils.py
index 2be96c1d3..a70aaae29 100644
--- a/utils.py
+++ b/utils.py
@@ -5,7 +5,7 @@
 # should be enabled
 
 import os
-import sys
+
 
 def get_list_from_file(file_path, list_name):
     '''Looks for a Python list called list_name in the file specified
@@ -121,4 +121,3 @@ def read_config_file():
     tests_enabled = get_bool_from_file(dot_ns3rc_path, 'tests_enabled', value_if_missing)
 
     return (config_file_exists, modules_enabled, examples_enabled, tests_enabled)
-
diff --git a/utils/grid.py b/utils/grid.py
index e8293af8c..61a07b37e 100644
--- a/utils/grid.py
+++ b/utils/grid.py
@@ -14,7 +14,7 @@ class DataRange:
     #  end
     ## @var value
     #  value
-    def __init__(self, start = 0, end = 0, value = ''):
+    def __init__(self, start=0, end=0, value=''):
         """! Initializer
         @param self this object
         @param start start
@@ -30,7 +30,7 @@ class EventString:
     #  at
     ## @var value
     #  value
-    def __init__(self, at = 0, value = ''):
+    def __init__(self, at=0, value=''):
         """! Initializer
         @param self this object
         @param at you
@@ -44,7 +44,7 @@ class EventFloat:
     #  at
     ## @var value
     #  value
-    def __init__(self, at = 0, value = 0.0):
+    def __init__(self, at=0, value=0.0):
         """! Initializer
         @param self this object
         @param at you
@@ -58,7 +58,7 @@ class EventInt:
     #  at
     ## @var value
     #  value
-    def __init__(self, at = 0, value = 0.0):
+    def __init__(self, at=0, value=0.0):
         """! Initializer
         @param self this object
         @param at you
@@ -88,7 +88,7 @@ class TimelineDataRange:
     #  name
     ## @var ranges
     #  ranges
-    def __init__(self, name = ''):
+    def __init__(self, name=''):
         """! Initializer
         @param self this object
         @param name name
@@ -154,13 +154,13 @@ class TimelineDataRange:
         s = self.__search(start)
         e = self.__search(end)
         if s == -1 and e == -1:
-            return(0, 0)
+            return (0, 0)
         elif s == -1:
-            return(0, e + 1)
+            return (0, e + 1)
         elif e == -1:
-            return(s, len(self.ranges))
+            return (s, len(self.ranges))
         else:
-            return(s, e + 1)
+            return (s, e + 1)
     def sort(self):
         """! Sort ranges
         @param self this object
@@ -175,16 +175,16 @@ class TimelineDataRange:
         if len(self.ranges) > 0:
             lo = self.ranges[0].start
             hi = self.ranges[len(self.ranges)-1].end
-            return(lo, hi)
+            return (lo, hi)
         else:
-            return(0, 0)
+            return (0, 0)
 ## TimelineEvent class
 class TimelineEvent:
     ## @var name
     #  name
     ## @var events
     #  events
-    def __init__(self, name = ''):
+    def __init__(self, name=''):
         """! Get ranges bounds
         @param self this object
         @param name name
@@ -235,7 +235,7 @@ class TimelineEvent:
         """
         s = self.__search(start)
         e = self.__search(end)
-        return(s, e + 1)
+        return (s, e + 1)
     def sort(self):
         """! Sort function
         @param self this object
@@ -250,9 +250,9 @@ class TimelineEvent:
         if len(self.events) > 0:
             lo = self.events[0].at
             hi = self.events[-1].at
-            return(lo, hi)
+            return (lo, hi)
         else:
-            return(0, 0)
+            return (0, 0)
 
 ## Timeline class
 class Timeline:
@@ -264,7 +264,7 @@ class Timeline:
     #  event string
     ## @var event_int
     #  event int
-    def __init__(self, name = ''):
+    def __init__(self, name=''):
         """! Initializer
         @param self this object
         @param name name
@@ -363,7 +363,7 @@ class Timeline:
                 lo = ev_lo
             if ev_hi > hi:
                 hi = ev_hi
-        return(lo, hi)
+        return (lo, hi)
 
 ## Timelines class
 class Timelines:
@@ -412,7 +412,7 @@ class Timelines:
                 lo = t_lo
             if t_hi > hi:
                 hi = t_hi
-        return(lo, hi)
+        return (lo, hi)
     def get_all_range_values(self):
         """! Get All Ranges
         @param self this object
@@ -433,7 +433,7 @@ class Color:
     #  green
     ## @var b
     #  blue
-    def __init__(self, r = 0.0, g = 0.0, b = 0.0):
+    def __init__(self, r=0.0, g=0.0, b=0.0):
         """! Initializer
         @param self: this object
         @param r: red
@@ -587,8 +587,6 @@ class TopLegendRenderer:
             ctx.show_text(legend)
             i += 1
 
-        return
-
 ## TimelinesRenderer class
 class TimelinesRenderer:
     ## @var padding
@@ -797,7 +795,7 @@ class TimelinesRenderer:
         for timeline in self.timelines.get_all():
             (y_bearing, t_width, t_height) = ctx.text_extents(timeline.name)[1:4]
             ctx.move_to(left_x_start, cur_y + self.max_text_height - (t_height + y_bearing))
-            ctx.show_text(timeline.name);
+            ctx.show_text(timeline.name)
             for events_int in timeline.get_events_int():
                 (y_bearing, t_width, t_height) = ctx.text_extents(events_int.name)[1:4]
                 ctx.move_to(right_x_start, cur_y + self.max_text_height - (t_height + y_bearing))
@@ -830,7 +828,6 @@ class TimelinesRenderer:
                        0, bot_y)
         self.draw_line(ctx, right_x_end + self.padding / 2, 0,
                        0, bot_y)
-        return
 
 ## ScaleRenderer class
 class ScaleRenderer:
@@ -869,7 +866,7 @@ class ScaleRenderer:
         @param x x
         @return real x
         """
-        real_x = (x - self.__lo ) * self.__width / (self.__hi - self.__lo)
+        real_x = (x - self.__lo) * self.__width / (self.__hi - self.__lo)
         return real_x
     def set_top(self):
         """! Set Top
@@ -899,7 +896,7 @@ class ScaleRenderer:
             closest *= 10
         if (data_delta / closest) == 0:
             delta = closest
-        elif(data_delta / closest) == 1:
+        elif (data_delta / closest) == 1:
             delta = closest / 10
         else:
             delta = closest
@@ -940,7 +937,7 @@ class ScaleRenderer:
         ctx.set_line_width(1.0)
         ticks = range(int(start), int(end + delta), int(delta))
         for x in ticks:
-            real_x = (x - self.__lo ) * self.__width / (self.__hi - self.__lo)
+            real_x = (x - self.__lo) * self.__width / (self.__hi - self.__lo)
             ctx.move_to(real_x, 0)
             ctx.line_to(real_x, 5*s)
             ctx.close_path()
@@ -958,7 +955,7 @@ class ScaleRenderer:
             start = self.__lo - (self.__lo % delta) + delta
             end = self.__hi - (self.__hi % delta)
             for x in range(int(start), int(end + delta), int(delta)):
-                real_x = (x - self.__lo ) * self.__width / (self.__hi - self.__lo)
+                real_x = (x - self.__lo) * self.__width / (self.__hi - self.__lo)
                 ctx.move_to(real_x, 0)
                 ctx.line_to(real_x, 3*s)
                 ctx.close_path()
@@ -1024,7 +1021,7 @@ class GraphicRenderer:
         """
         y_start = self.__top_legend.get_height()
         x_start = self.__data.get_data_x_start()
-        return(x_start, y_start, self.__width - x_start, self.__data.get_height())
+        return (x_start, y_start, self.__width - x_start, self.__data.get_height())
     def scale_data(self, x):
         """! Get Data Rectangle
         @param self this object
@@ -1044,7 +1041,7 @@ class GraphicRenderer:
         y_height = self.__bot_scale.get_height() + 20
         x_start = self.__bot_scale.get_position(self.__r_start)
         x_end = self.__bot_scale.get_position(self.__r_end)
-        return(x_start, y_start, x_end - x_start, y_height)
+        return (x_start, y_start, x_end - x_start, y_height)
     def scale_selection(self, x):
         """! Scale Selection
         @param self this object
@@ -1074,7 +1071,7 @@ class GraphicRenderer:
         @param self this object
         @return range
         """
-        return(self.__r_start, self.__r_end)
+        return (self.__r_start, self.__r_end)
     def set_data(self, data):
         """! Set Date
         @param self this object
@@ -1144,14 +1141,14 @@ class GraphicRenderer:
         # data
         ctx.save()
         ctx.translate(0,
-                       top_legend_height)
+                      top_legend_height)
         self.__data.draw(ctx)
         ctx.restore()
 
         # scale below data
         ctx.save()
         ctx.translate(self.__data.get_data_x_start(),
-                       top_legend_height + self.__data.get_height() + self.__mid_scale.get_height())
+                      top_legend_height + self.__data.get_height() + self.__mid_scale.get_height())
         self.__mid_scale.draw(ctx)
         ctx.restore()
 
@@ -1177,7 +1174,7 @@ class GraphicRenderer:
         select_end = self.__bot_scale.get_position(self.__r_end)
 
         # left connection between top scale and bottom scale
-        ctx.move_to(0, height_used);
+        ctx.move_to(0, height_used)
         ctx.line_to(self.__data.get_data_x_start(), height_used)
         ctx.line_to(select_start, height_used + 20)
         ctx.line_to(0, height_used + 20)
@@ -1206,12 +1203,12 @@ class GraphicRenderer:
         unused_end = self.__bot_scale.get_position(self.__r_end)
         unused_height = self.__bot_scale.get_height() + 20
         ctx.rectangle(0, height_used,
-                       unused_start,
-                       unused_height)
+                      unused_start,
+                      unused_height)
         ctx.rectangle(unused_end,
-                       height_used,
-                       self.__width - unused_end,
-                       unused_height)
+                      height_used,
+                      self.__width - unused_end,
+                      unused_height)
         ctx.set_source_rgb(0.9, 0.9, 0.9)
         ctx.fill()
 
@@ -1584,7 +1581,6 @@ class MainWindow:
         dialog.set_default_response(1)
         dialog.connect("response", self.__dialog_response_cb)
         dialog.show()
-        return
     def __dialog_response_cb(self, widget, response):
         """! Dialog Response Callback
         @param self this object
@@ -1596,7 +1592,6 @@ class MainWindow:
             filename = self.__dialog.get_filename()
             self.__render.output_png(filename)
             widget.hide()
-        return
 
 
 ## read_data function
@@ -1654,7 +1649,6 @@ def read_data(filename):
     return (colors, timelines)
 
 
-
 def main():
     (colors, timelines) = read_data(sys.argv[1])
     (lower_bound, upper_bound) = timelines.get_bounds()
diff --git a/utils/tests/TestBase.py b/utils/tests/TestBase.py
index b23aaddbc..0bf6ef3c2 100644
--- a/utils/tests/TestBase.py
+++ b/utils/tests/TestBase.py
@@ -24,9 +24,9 @@ import os
 
 def print_case_in_file(case_string, out):
     for i in range(100):
-        print("-", end = '', file = out)
+        print("-", end='', file=out)
     print(file=out)
-    print("running test case " + case_string, end='\n\n', file = out)
+    print("running test case " + case_string, end='\n\n', file=out)
     out.flush()
 
 def print_failed_cases(failed_cases):
@@ -40,10 +40,10 @@ def print_cmds(cmds):
         print(cmd.replace(sys.executable, ''))
 
 def set_workdir():
-    dir_files = [ f for f in os.listdir('.') if os.path.exists(f) ]
+    dir_files = [f for f in os.listdir('.') if os.path.exists(f)]
     if not 'VERSION' in dir_files and not 'ns3' in dir_files:
         if os.path.split(os.path.abspath('.'))[1] == 'tests' and os.path.split(os.path.abspath(os.pardir))[1] == 'utils':
-                os.chdir('../../')
+            os.chdir('../../')
         else:
             print('Error: Invalid working directory')
             sys.exit(1)
@@ -75,7 +75,7 @@ class TestBaseClass:
         self.my_env['LD_LIBRARY_PATH'] = os.getcwd() + "/build"
         self.mode = mode
         self.outfile = 'test-port-'+self.mode+'.out'
-        self.options = self.parseargs(argv , desc)
+        self.options = self.parseargs(argv, desc)
 
     def parseargs(self, argv, desc):
         """!
@@ -85,15 +85,15 @@ class TestBaseClass:
         @param desc description
         @return command line arguments
         """
-        parser = argparse.ArgumentParser(description = desc)
-        parser.add_argument('-f', '--file', action='store', dest='out_file', default = self.outfile,
+        parser = argparse.ArgumentParser(description=desc)
+        parser.add_argument('-f', '--file', action='store', dest='out_file', default=self.outfile,
                             metavar="FILE",
                             help='File to be used for storing the command specific output (Default: '+self.outfile+')')
         parser.add_argument('-c', action='store_true', dest='cmds', default=False,
                             help='List out all the commands being tested')
         parser.add_argument('-m', action='store_true', dest='mute', default=False,
                             help='Sends only stderr output to FILE')
-        parser.add_argument('-x', '--customcmd', action='store', dest='custcmd', default = None,
+        parser.add_argument('-x', '--customcmd', action='store', dest='custcmd', default=None,
                             help='Enter a comma-separated list of commands to override the existing ones. NOT APPLICABLE FOR TEST-PY SUITE.')
         return parser.parse_args(argv)
 
@@ -142,5 +142,5 @@ class TestBaseClass:
             print_failed_cases(failed_cases)
         else:
             print("\nAll cases passed")
-        print ("Detailed output available in " + self.options.out_file, end='\n\n')
+        print("Detailed output available in " + self.options.out_file, end='\n\n')
         return final_return
diff --git a/utils/tests/test-test.py b/utils/tests/test-test.py
index 519da4f3d..96a6197a5 100644
--- a/utils/tests/test-test.py
+++ b/utils/tests/test-test.py
@@ -71,49 +71,49 @@ def main(argv):
         Prepares test cases and executes
     """
     test_cases = [
-      '',
-      '-h',
-      '--help',
-      '-b build/',
-      '--buildpath=build/',
-      '-c performance',
-      '--constrain=performance',
-      '-d',
-      '--duration',
-      '-e socket-options-ipv6',
-      '--example=socket-options-ipv6',
-      '-u',
-      '--update-data',
-      '-f EXTENSIVE --fullness=EXTENSIVE'
-      '-g',
-      '--grind',
-      '-l',
-      '--list',
-      '-m',
-      '--multiple',
-      '-n',
-      '--no-build',
-      '-p first',
-      '--pyexample=first',
-      '-r',
-      '--retain',
-      '-s ns3-tcp-interoperability',
-      '--suite=ns3-tcp-interoperability',
-      '-t t_opt.txt',
-      '--text=t_opt.txt && rm -rf t_opt.txt',
-      '-v',
-      '--verbose',
-      '-w t_opt.html && rm -rf t_opt.html',
-      '--web=t_opt.html && rm -rf t_opt.html',
-      '--html=t_opt.html && rm -rf t_opt.html',
-      '-x t_opt.xml && rm -rf t_opt.xml',
-      '--xml=t_opt.xml && rm -rf t_opt.xml',
+        '',
+        '-h',
+        '--help',
+        '-b build/',
+        '--buildpath=build/',
+        '-c performance',
+        '--constrain=performance',
+        '-d',
+        '--duration',
+        '-e socket-options-ipv6',
+        '--example=socket-options-ipv6',
+        '-u',
+        '--update-data',
+        '-f EXTENSIVE --fullness=EXTENSIVE'
+        '-g',
+        '--grind',
+        '-l',
+        '--list',
+        '-m',
+        '--multiple',
+        '-n',
+        '--no-build',
+        '-p first',
+        '--pyexample=first',
+        '-r',
+        '--retain',
+        '-s ns3-tcp-interoperability',
+        '--suite=ns3-tcp-interoperability',
+        '-t t_opt.txt',
+        '--text=t_opt.txt && rm -rf t_opt.txt',
+        '-v',
+        '--verbose',
+        '-w t_opt.html && rm -rf t_opt.html',
+        '--web=t_opt.html && rm -rf t_opt.html',
+        '--html=t_opt.html && rm -rf t_opt.html',
+        '-x t_opt.xml && rm -rf t_opt.xml',
+        '--xml=t_opt.xml && rm -rf t_opt.xml',
     ]
 
     configure_string = sys.executable + ' ns3 configure --enable-tests --enable-examples'
     clean_string = sys.executable + ' ns3 clean'
-    cmd_execute_list = [ '%s && %s test.py %s && %s' % (configure_string, sys.executable, option, clean_string) for option in test_cases]
-    runner = TestBaseClass(argv[1:], "Test suite for the ns-3 unit test runner" , 'test-py')
+    cmd_execute_list = ['%s && %s test.py %s && %s' % (configure_string, sys.executable, option, clean_string) for option in test_cases]
+    runner = TestBaseClass(argv[1:], "Test suite for the ns-3 unit test runner", 'test-py')
     return runner.runtests(cmd_execute_list)
 
 if __name__ == '__main__':