Use Counter instead of dict

Author: mikulatomas

concepts/algorithms/covering_edges.py

@@ -5,6 +5,8 @@
 John Wiley & Sons, 2004.
 """
 
+from collections import Counter
+
 from .fcbo import fast_generate_from
 
 
@@ -89,7 +91,7 @@ def covering_edges(concept_list, context):
     concept_index = dict(concept_list)
 
     for extent, intent in concept_index.items():
-        candidate_counter = dict()
+        candidate_counter = Counter()
 
         property_candidates = Properties.fromint(Properties.supremum & ~intent)