Index: darg.py
==================================================================
--- darg.py
+++ darg.py
@@ -6,12 +6,10 @@
 
 # by Olivier R.
 # License: MPL 2
 
 import re
-import traceback
-
 
 
 class DARG:
     """DIRECT ACYCLIC RULE GRAPH"""
     # This code is inspired from Steve Hanov’s DAWG, 2011. (http://stevehanov.ca/blog/index.php?id=115)
@@ -55,11 +53,11 @@
         # Check the lUncheckedNodes for redundant nodes, proceeding from last
         # one down to the common prefix size. Then truncate the list at that point.
         self._minimize(nCommonPrefix)
 
         # add the suffix, starting from the correct node mid-way through the graph
-        if len(self.lUncheckedNodes) == 0:
+        if not self.lUncheckedNodes:
             oNode = self.oRoot
         else:
             oNode = self.lUncheckedNodes[-1][2]
 
         iToken = nCommonPrefix
@@ -127,32 +125,32 @@
             dKeyTrans[nKey] = i
         # replace keys
         dNewGraph = {}
         for nKey, dVal in dGraph.items():
             dNewGraph[dKeyTrans[nKey]] = dVal
-        for nKey, dVal in dGraph.items():
+        for _, dVal in dGraph.items():
             for sArc, val in dVal.items():
-                if type(val) is int:
+                if isinstance(val, int):
                     dVal[sArc] = dKeyTrans[val]
                 else:
-                    for sArc, nKey in val.items():
-                        val[sArc] = dKeyTrans[nKey]
+                    for sArc2, nKey in val.items():
+                        val[sArc2] = dKeyTrans[nKey]
         return dNewGraph
 
     def _sortActions (self, dGraph):
         "when a pattern is found, several actions may be launched, and it must be performed in a certain order"
-        for nKey, dVal in dGraph.items():
+        for _, dVal in dGraph.items():
             if "<rules>" in dVal:
-                for sLineId, nKey in dVal["<rules>"].items():
+                for _, nKey in dVal["<rules>"].items():
                     # we change the dictionary of actions in a list of actions (values of dictionary all points to the final node)
                     if isinstance(dGraph[nKey], dict):
                         dGraph[nKey] = sorted(dGraph[nKey].keys())
 
     def _checkRegexes (self, dGraph):
         "check validity of regexes"
         aRegex = set()
-        for nKey, dVal in dGraph.items():
+        for _, dVal in dGraph.items():
             if "<re_value>" in dVal:
                 for sRegex in dVal["<re_value>"]:
                     if sRegex not in aRegex:
                         self._checkRegex(sRegex)
                         aRegex.add(sRegex)
@@ -171,19 +169,19 @@
                 if not sNegPattern:
                     print("# Warning! Empty negpattern:", sRegex)
                 re.compile(sPattern)
                 if sNegPattern != "*":
                     re.compile(sNegPattern)
-            except:
+            except re.error:
                 print("# Error. Wrong regex:", sRegex)
                 exit()
         else:
             try:
                 if not sRegex:
                     print("# Warning! Empty pattern:", sRegex)
                 re.compile(sRegex)
-            except:
+            except re.error:
                 print("# Error. Wrong regex:", sRegex)
                 exit()
 
 
 class Node: