Fixed infinite recursion when parsing complex BNF node

src/core/sheerka/services/SheerkaExecute.py

@@ -173,6 +173,17 @@ class SheerkaExecute(BaseService):
         return pi
 
     def call_parsers(self, context, return_values):
+        """
+        Call all the parsers, ordered by priority
+        Possible return value for a parser:
+            None : indicate that you do no need to care about the result
+            ParserResult with status False : Success
+            ParserResult with status False : failed to parse, but the result will be reused by other parsers
+            NotForMe (status is False) : Failed to parse. Do no reuse the result
+        :param context:
+        :param return_values:
+        :return:
+        """
 
         # return_values must be a list
         if not isinstance(return_values, list):