First steps of ConceptLexer. Need to update DefaultParser before continuing

sdp/sheerkaDataProvider.py

@@ -129,7 +129,7 @@ class State:
         if digest is None:
             return
 
-        if not isinstance(items, list):
+        if not hasattr(items, "__iter__"):
             items = [items]
 
         for item in items:
@@ -575,9 +575,9 @@ class SheerkaDataProvider:
     def exists(self, entry, key=None, digest=None):
         """
         Returns true if the entry is defined
-        :param digest:
         :param key:
         :param entry:
+        :param digest: digest of the object, when several entries share the same key
         :return:
         """
         snapshot = self.get_snapshot()