diff --git a/library/cadbiom/models/clause_constraints/mcl/MCLSolutions.py b/library/cadbiom/models/clause_constraints/mcl/MCLSolutions.py
index 96c6bd5b0d4758aa77bc11f5087f054a3e9eea21..fbac5db82c289fbda8f9dbae787dca0953cda6f1 100644
--- a/library/cadbiom/models/clause_constraints/mcl/MCLSolutions.py
+++ b/library/cadbiom/models/clause_constraints/mcl/MCLSolutions.py
@@ -588,7 +588,7 @@ class FrontierSolution(object):
         return self.activated_frontier == other.activated_frontier
 
     def __ne__(self, other):
-        """Python 2 ..."""
+        """Python 2 requires this in conjunction to __eq__..."""
         return self.__eq__(other)
 
     def __hash__(self):
@@ -680,6 +680,7 @@ class DimacsFrontierSol(object):
         # Pre-compute nb of activated frontiers in the current solution
         # PS: use numpy to accelerate this ? The cast is costly...
         # We could keep a separated function and use lru_cache instead...
+        ## TODO: replace by len() call magic method
         self.nb_activated_frontiers = len(self.activated_frontier_values)
 
     @classmethod
@@ -769,7 +770,7 @@ class DimacsFrontierSol(object):
         return self.activated_frontier_values == other.activated_frontier_values
 
     def __ne__(self, other):
-        """Python 2 ..."""
+        """Python 2 requires this in conjunction to __eq__..."""
         return self.__eq__(other)
 
     def __hash__(self):