Implemented some enhancement requests

src/core/builtin_helpers.py

@@ -7,7 +7,7 @@ from core.sheerka.services.SheerkaExecute import SheerkaExecute
 from core.tokenizer import Keywords
 from parsers.BaseNodeParser import SourceCodeNode, ConceptNode, UnrecognizedTokensNode, SourceCodeWithConceptNode, \
     RuleNode
-from parsers.BaseParser import BaseParser, ErrorNode
+from parsers.BaseParser import BaseParser, ParsingError
 
 PARSE_STEPS = [BuiltinConcepts.BEFORE_PARSING, BuiltinConcepts.PARSING, BuiltinConcepts.AFTER_PARSING]
 EVAL_STEPS = PARSE_STEPS + [BuiltinConcepts.BEFORE_EVALUATION, BuiltinConcepts.EVALUATION,
@@ -254,7 +254,7 @@ def only_parsers_results(context, return_values):
     # hack because some parsers don't follow the NOT_FOR_ME rule
     temp_ret_val = []
     for ret_val in return_values_ok:
-        if isinstance(ret_val.body.body, ErrorNode):
+        if isinstance(ret_val.body.body, ParsingError):
             continue
         if isinstance(ret_val.body.body, list) and \
             len(ret_val.body.body) == 1 and \