Fix logging of non-serializable object (Python 2)

Direct call of __repr__ method causes Python failure in Python 2.
Actual code works only in Python 3.
repr() call works in both Python 2/3.

Author: mbirger

kafka_logger/handlers.py

@@ -160,7 +160,7 @@ def prepare_record_dict(self, record):
                     # Elasticsearch supports number datatypes
                     # but it is not 1:1 - logging "inf" float
                     # causes _jsonparsefailure error in ELK
-                    value = tuple(arg.__repr__() for arg in value)
+                    value = tuple(repr(arg) for arg in value)
                 rec[key] = "" if value is None else value
 
         return rec