satisfy pycodestyle checker

src/AbstractDataObject.py

@@ -1,12 +1,14 @@
 import re
 import json
 
+
 class InvalidDataObjectException(Exception):
     def __init__(self, message):
         super().__init__(message)
 
+
 class AbstractDataObject(object):
-    invalidChars = re.compile("[#+\s]")
+    invalidChars = re.compile(r'[#+\s]')
 
     def __init__(self, topicPart):
         self.topicPart = topicPart
@@ -17,4 +19,4 @@ class AbstractDataObject(object):
         return self.topicPart
 
     def getPayload(self):
-        raise NotImplementedError()
+        raise NotImplementedError()