Fixed check_output_folder to ensure the folder exists and does not re…

…ferences to a file. Fixed memory reference on simple assignments.

src/vtlengine/API/_InternalApi.py

@@ -319,7 +319,9 @@ def _check_output_folder(output_folder: Union[str, Path]):
         except Exception:
             raise Exception('Output folder must be a Path or S3 URI to a directory')
 
-    if not isinstance(output_folder, Path) or not output_folder.is_dir():
+    if not isinstance(output_folder, Path):
         raise Exception('Output folder must be a Path or S3 URI to a directory')
     if not output_folder.exists():
+        if output_folder.suffix != '':
+            raise Exception('Output folder must be a Path or S3 URI to a directory')
         os.mkdir(output_folder)

src/vtlengine/Interpreter/__init__.py

@@ -158,7 +158,7 @@ def visit_Start(self, node: AST.Start) -> Any:
             if result is None:
                 continue
             # Save results
-            self.datasets[result.name] = result
+            self.datasets[result.name] = copy(result)
             results[result.name] = result
             self._save_datapoints_efficient(statement_num)
             statement_num += 1