fixed #18 : I can evaluate concept

src/core/error.py

@@ -1,6 +1,7 @@
 from dataclasses import dataclass
 
 from common.utils import compute_hash
+from core.BuiltinConcepts import BuiltinConcepts
 from core.ExecutionContext import ExecutionContext
 
 
@@ -23,7 +24,7 @@ class ErrorObj:
         pass
 
 
-class ErrorContext:
+class ErrorContext(ErrorObj):
     """
     This class represents the result of a data flow processing
     """
@@ -63,3 +64,8 @@ class ErrorContext:
                 temp.append(repr(value))
 
         return ", ".join(temp)
+
+
+ErrorConcepts = {BuiltinConcepts.UNKNOWN_CONCEPT,
+                 BuiltinConcepts.EVALUATION_ERROR,
+                 BuiltinConcepts.INVALID_CONCEPT}