FEATURE: More helpful error message with safeZip

Before it was necessary to debug the error to see what
was unbalanced.  Now it prints out the list of lists directly
with the length of each sublist in a formatted manner.

lmeds/utilities/utils.py

@@ -18,6 +18,21 @@
 import math
 
 
+class UnbalancedListsError(Exception):
+
+    def __init__(self, listOfLists):
+        super(UnbalancedListsError, self).__init__()
+
+        self.listOfLists = listOfLists
+
+    def __str__(self):
+        retStr = "All sublists must be the same length.\n"
+        for subList in self.listOfLists:
+            retStr += "Length:%04d,List:%s\n" % (len(subList), subList)
+
+        return retStr
+
+
 def decodeUnicode(inputStr):
 
     # Python 2-to-3 compatibility hack
@@ -127,7 +142,8 @@ def safeZip(listOfLists, enforceLength):
 
     if enforceLength is True:
         length = len(listOfLists[0])
-        assert(all([length == len(subList) for subList in listOfLists]))
+        if not all([length == len(subList) for subList in listOfLists]):
+            raise UnbalancedListsError(listOfLists)
 
     return zip_longest(*listOfLists)