add requirement to overwrite document_type if super method returns a …

…type

src/pie_modules/taskmodules/common/taskmodule_with_document_converter.py

@@ -1,13 +1,12 @@
 from abc import ABC, abstractmethod
-from typing import Generic, Iterable, Iterator, Optional, Sequence, TypeVar, Union
+from typing import Generic, Iterable, Iterator, Optional, Sequence, Type, TypeVar, Union
 
 from pytorch_ie import Document, TaskEncoding, TaskModule
 from pytorch_ie.core.taskmodule import (
     IterableTaskEncodingDataset,
     TaskEncodingDataset,
     TaskEncodingSequence,
 )
-from pytorch_ie.documents import TextDocumentWithLabeledSpansAndBinaryRelations
 from typing_extensions import TypeAlias
 
 DocumentType = TypeVar("DocumentType", bound=Document)
@@ -40,6 +39,13 @@ class TaskModuleWithDocumentConverter(
         TaskOutputType,
     ],
 ):
+    @property
+    def document_type(self) -> Optional[Type[Document]]:
+        if super().document_type is not None:
+            raise NotImplementedError(f"please overwrite document_type for {type(self).__name__}")
+        else:
+            return None
+
     @abstractmethod
     def _convert_document(self, document: DocumentType) -> ConvertedDocumentType:
         """Convert a document of the taskmodule document type to the expected document type of the
@@ -100,7 +106,7 @@ def _integrate_predictions_from_converted_document(
         self,
         document: DocumentType,
         converted_document: ConvertedDocumentType,
-    ) -> TextDocumentWithLabeledSpansAndBinaryRelations:
+    ) -> None:
         """Convert the predictions at the respective layers of the converted_document and add them
         to the original document predictions.