diff --git a/sw/lib/python/ivy_msg_interface.py b/sw/lib/python/ivy_msg_interface.py
index 1885f039bd..035593b291 100644
--- a/sw/lib/python/ivy_msg_interface.py
+++ b/sw/lib/python/ivy_msg_interface.py
@@ -1,4 +1,4 @@
-from __future__ import absolute_import, print_function
+from __future__ import absolute_import, division, print_function
 
 from ivy.std_api import *
 import logging
diff --git a/sw/lib/python/pprz_msg/message.py b/sw/lib/python/pprz_msg/message.py
index d2579e3252..9bfeb3934c 100644
--- a/sw/lib/python/pprz_msg/message.py
+++ b/sw/lib/python/pprz_msg/message.py
@@ -3,23 +3,26 @@ Paparazzi message representation
 
 """
 
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function
 import sys
 import json
 import struct
-import messages_xml_map
+from . import messages_xml_map
+
 
 class PprzMessageError(Exception):
     def __init__(self, message, inner_exception=None):
         self.message = message
         self.inner_exception = inner_exception
         self.exception_info = sys.exc_info()
+
     def __str__(self):
         return self.message
 
 
 class PprzMessage(object):
     """base Paparazzi message class"""
+
     def __init__(self, class_name, name):
         self._class_name = class_name
         self._name = name
@@ -67,21 +70,21 @@ class PprzMessage(object):
         return self._fieldtypes
 
     def fieldbintypes(self, t):
-        """Get type and lenfth for binary format"""
+        """Get type and length for binary format"""
         data_types = {
-                'float': ['f', 4],
-                'uint8': ['B', 1],
-                'uint16': ['H', 2],
-                'uint32': ['L', 4],
-                'int8': ['b', 1],
-                'int16': ['h', 2],
-                'int32': ['l', 4],
-                'char': ['c', 1]
-                }
-        baseType = t
+            'float': ['f', 4],
+            'uint8': ['B', 1],
+            'uint16': ['H', 2],
+            'uint32': ['L', 4],
+            'int8': ['b', 1],
+            'int16': ['h', 2],
+            'int32': ['l', 4],
+            'char': ['c', 1]
+        }
+        base_type = t
         if t[-2:] == "[]":
-            baseType = t[:-2]
-        return data_types[baseType]
+            base_type = t[:-2]
+        return data_types[base_type]
 
     def get_field(self, idx):
         """Get field value by index."""
@@ -98,7 +101,7 @@ class PprzMessage(object):
         if len(values) == len(self.fieldnames):
             self._fieldvalues = values
         else:
-            print("set values %i %i" %(len(values), len(self.fieldnames)))
+            print("set values %i %i" % (len(values), len(self.fieldnames)))
             raise PprzMessageError("Error: fields not matching")
 
     def set_value_by_name(self, name, value):
@@ -145,8 +148,8 @@ class PprzMessage(object):
         data = []
         length = 0
         for idx, t in enumerate(self.fieldtypes):
-            binType = self.fieldbintypes(t)
-            struct_string += binType[0]
+            bin_type = self.fieldbintypes(t)
+            struct_string += bin_type[0]
             array_length = 1
             if "char[" in t:
                 array_length = len(self.fieldvalues[idx])
@@ -158,7 +161,7 @@ class PprzMessage(object):
                     data.append(x)
             else:
                 data.append(self.fieldvalues[idx])
-            length += binType[1] * array_length
+            length += bin_type[1] * array_length
         msg = struct.pack(struct_string, *data)
         return msg
 
@@ -166,24 +169,25 @@ class PprzMessage(object):
         msg_offset = 0
         values = []
         for idx, t in enumerate(self.fieldtypes):
-            binType = self.fieldbintypes(t)
+            bin_type = self.fieldbintypes(t)
             if t[-2:] == "[]":
                 array_length = int(struct.unpack('<B', data[msg_offset])[0])
-                msg_offset = msg_offset + 1
+                msg_offset += 1
                 array_value = []
                 for count in range(0, array_length):
-                    array_value.append(struct.unpack('<'+binType[0], "".join(data[msg_offset:msg_offset+binType[1]])))
-                    msg_offset = msg_offset + binType[1]
+                    array_value.append(struct.unpack('<' + bin_type[0], "".join(data[msg_offset:msg_offset + bin_type[1]])))
+                    msg_offset = msg_offset + bin_type[1]
                 values.append(array_value)
             else:
-                value = struct.unpack('<'+binType[0], "".join(data[msg_offset:msg_offset+binType[1]]))
-                msg_offset = msg_offset + binType[1]
+                value = struct.unpack('<' + bin_type[0], "".join(data[msg_offset:msg_offset + bin_type[1]]))
+                msg_offset = msg_offset + bin_type[1]
                 values.append(value)
         self.set_values(values)
 
 
 def test():
     import argparse
+
     parser = argparse.ArgumentParser()
     parser.add_argument("-f", "--file", help="path to messages.xml file")
     parser.add_argument("-c", "--class", help="message class", dest="msg_class", default="telemetry")
@@ -194,5 +198,6 @@ def test():
     for msg in messages:
         print(msg)
 
+
 if __name__ == '__main__':
     test()
diff --git a/sw/lib/python/pprz_msg/messages_xml_map.py b/sw/lib/python/pprz_msg/messages_xml_map.py
index 1ecd676f8c..3d5ec2d37d 100755
--- a/sw/lib/python/pprz_msg/messages_xml_map.py
+++ b/sw/lib/python/pprz_msg/messages_xml_map.py
@@ -72,6 +72,7 @@ def get_msgs(msg_class):
         print("Error: msg_class %s not found." % msg_class)
     return []
 
+
 def get_msg_name(msg_class, msg_id):
     if not message_dictionary:
         parse_messages()
@@ -84,6 +85,7 @@ def get_msg_name(msg_class, msg_id):
         print("Error: msg_class %s not found." % msg_class)
     return ""
 
+
 def get_msg_fields(msg_class, msg_name):
     if not message_dictionary:
         parse_messages()
diff --git a/sw/lib/python/pprz_msg/pprz_transport.py b/sw/lib/python/pprz_msg/pprz_transport.py
index 9250cf6f77..e1961e03cc 100644
--- a/sw/lib/python/pprz_msg/pprz_transport.py
+++ b/sw/lib/python/pprz_msg/pprz_transport.py
@@ -3,11 +3,17 @@ Paparazzi transport encoding utilities
 
 """
 
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function
 import struct
-from pprz_msg.message import PprzMessage
-import messages_xml_map
-from enum import Enum
+from .message import PprzMessage
+from . import messages_xml_map
+
+# use Enum from python 3.4 if available (https://www.python.org/dev/peps/pep-0435/)
+# (backports as enum34 on pypi)
+try:
+    from enum import Enum
+except ImportError:
+    Enum = object
 
 STX = 0x99
 STX_TS = 0x98
@@ -47,7 +53,7 @@ class PprzTransport(object):
             self.idx = 0
             self.state = PprzParserState.GotLength
         elif self.state == PprzParserState.GotLength:
-            self.buf.append(c);
+            self.buf.append(c)
             self.ck_a = (self.ck_a + b) % 256
             self.ck_b = (self.ck_b + self.ck_a) % 256
             self.idx += 1
@@ -77,7 +83,7 @@ class PprzTransport(object):
         msg_name = messages_xml_map.get_msg_name(msg_class, msg_id)
         msg = PprzMessage(msg_class, msg_name)
         msg.binary_to_payload(data[2:])
-        return (sender_id, msg)
+        return sender_id, msg
 
     def unpack(self):
         """Unpack the last received message"""
@@ -90,7 +96,7 @@ class PprzTransport(object):
         for c in msg[1:]:
             ck_a = (ck_a + ord(c)) % 256
             ck_b = (ck_b + ck_a) % 256
-        return (ck_a, ck_b)
+        return ck_a, ck_b
 
     def pack_pprz_msg(self, sender, msg):
         data = msg.payload_to_binary()
@@ -98,6 +104,6 @@ class PprzTransport(object):
         length = 6 + len(data)
         msg = struct.pack("<BBBB", STX, length, sender, msg.msg_id) + data
         (ck_a, ck_b) = self.calculate_checksum(msg)
-        msg = msg + struct.pack('<BB', ck_a, ck_b)
+        msg += struct.pack('<BB', ck_a, ck_b)
         return msg
 
diff --git a/sw/lib/python/serial_msg_interface.py b/sw/lib/python/serial_msg_interface.py
index afe897c5d5..6ec10d6cf5 100644
--- a/sw/lib/python/serial_msg_interface.py
+++ b/sw/lib/python/serial_msg_interface.py
@@ -1,4 +1,4 @@
-from __future__ import absolute_import, print_function
+from __future__ import absolute_import, division, print_function
 
 import threading
 import serial
@@ -17,7 +17,8 @@ import pprz_msg.messages_xml_map
 
 
 class SerialMessagesInterface(threading.Thread):
-    def __init__(self, callback, init=True, verbose=False, device='/dev/ttyUSB0', baudrate=115200, msg_class='telemetry', messages_file=''):
+    def __init__(self, callback, init=True, verbose=False, device='/dev/ttyUSB0', baudrate=115200,
+                 msg_class='telemetry'):
         threading.Thread.__init__(self)
         self.callback = callback
         self.verbose = verbose
@@ -25,11 +26,10 @@ class SerialMessagesInterface(threading.Thread):
         self.running = True
         try:
             self.ser = serial.Serial(device, baudrate, timeout=1.0)
-        except:
+        except serial.SerialException:
             print("Error: unable to open serial port '%s'" % device)
             exit(0)
         self.trans = PprzTransport(msg_class)
-        pprz_msg.messages_xml_map.parse_messages(messages_file)
 
     def stop(self):
         print("End thread and close serial link")
@@ -71,20 +71,26 @@ class SerialMessagesInterface(threading.Thread):
 
 # FIXME not working because of the thread ?
 import signal
+
+
 def signal_term_handler(signal, frame):
-        print("got SIGINT")
-        #sys.exit(0)
+    print("got SIGINT")
+    # sys.exit(0)
+
 
 def test():
     signal.signal(signal.SIGINT, signal_term_handler)
     import argparse
+
     parser = argparse.ArgumentParser()
     parser.add_argument("-f", "--file", help="path to messages.xml file")
     parser.add_argument("-c", "--class", help="message class", dest='msg_class', default='telemetry')
     parser.add_argument("-d", "--device", help="device name", dest='dev', default='/dev/ttyUSB0')
     parser.add_argument("-b", "--baudrate", help="baudrate", dest='baud', default=115200, type=int)
     args = parser.parse_args()
-    serial_interface = SerialMessagesInterface(lambda s, m : print("new message from %i: %s" % (s, m)), device = args.dev, baudrate = args.baud, msg_class=args.msg_class, messages_file=args.file, verbose=True)
+    pprz_msg.messages_xml_map.parse_messages(args.file)
+    serial_interface = SerialMessagesInterface(lambda s, m: print("new message from %i: %s" % (s, m)), device=args.dev,
+                                               baudrate=args.baud, msg_class=args.msg_class, verbose=True)
     att_msg = PprzMessage('telemetry', 'ATTITUDE')
     att_msg.set_value_by_name('phi', 0.1)
     att_msg.set_value_by_name('theta', 0.2)
@@ -99,5 +105,6 @@ def test():
     serial_interface.stop()
     serial_interface.join()
 
+
 if __name__ == '__main__':
     test()