Fix reverse noderange in python 3

python3 environments do not natively know the word 'unicode',
in such a case, make unicode an alias for 'str'.

confluent_server/confluent/core.py

@@ -69,6 +69,10 @@ import sys
 pluginmap = {}
 dispatch_plugins = (b'ipmi', u'ipmi', b'redfish', u'redfish', b'tsmsol', u'tsmsol')
 
+try:
+    unicode
+except NameError:
+    unicode = str
 
 def seek_element(currplace, currkey):
     try: