I can define and eval BNF definitions

parsers/ExactConceptParser.py

@@ -1,7 +1,7 @@
 from core.builtin_concepts import ReturnValueConcept, BuiltinConcepts
 from parsers.BaseParser import BaseParser
 from core.tokenizer import Tokenizer, Keywords, TokenKind
-from core.concept import Concept, VARIABLE_PREFIX
+from core.concept import VARIABLE_PREFIX
 import logging
 
 log = logging.getLogger(__name__)
@@ -14,7 +14,7 @@ class ExactConceptParser(BaseParser):
 
     MAX_WORDS_SIZE = 10
 
-    def __init__(self):
+    def __init__(self, **kwargs):
         BaseParser.__init__(self, "ConceptParser")
 
     def parse(self, context, text):