DataSource initializer needs keyword argument 'block_size'.

cml/usecases/query.py

@@ -7,7 +7,9 @@ class PreprocessUsecase(Usecase):
         preprocesser = Preprocessor(request.pre_settings)
         cleaned_data = preprocesser.clean(request.source_adapter)
         learnblock_identifier = LearnblockIdentifier(request.block_settings)
-        data_source = DataSource(cleaned_data, learnblock_identifier)
+        data_source = DataSource(cleaned_data,
+                                 learnblock_identifier,
+                                 block_size=request.block_settings.block_size)
         return data_source