First steps of ConceptLexer. Need to update DefaultParser before continuing

parsers/BaseParser.py

@@ -51,6 +51,10 @@ class BaseParser:
         if tokens is None:
             return ""
         res = ""
+
+        if not hasattr(tokens, "__iter__"):
+            tokens = [tokens]
+
         for token in tokens:
             value = Keywords(token.value).value if token.type == TokenKind.KEYWORD else token.value
             res += value