diff --git a/docling/backend/abstract_backend.py b/docling/backend/abstract_backend.py
index be4c4a5..99b7981 100644
--- a/docling/backend/abstract_backend.py
+++ b/docling/backend/abstract_backend.py
@@ -35,7 +35,7 @@ class PdfPageBackend(ABC):
 
 class PdfDocumentBackend(ABC):
     @abstractmethod
-    def __init__(self, path_or_stream: Iterable[Union[BytesIO, Path]]):
+    def __init__(self, path_or_stream: Union[BytesIO, Path]):
         pass
 
     @abstractmethod
diff --git a/docling/backend/docling_parse_backend.py b/docling/backend/docling_parse_backend.py
index 1e4bc63..31a2582 100644
--- a/docling/backend/docling_parse_backend.py
+++ b/docling/backend/docling_parse_backend.py
@@ -146,11 +146,12 @@ class DoclingParsePageBackend(PdfPageBackend):
 
 
 class DoclingParseDocumentBackend(PdfDocumentBackend):
-    def __init__(self, path_or_stream: Iterable[Union[BytesIO, Path]]):
+    def __init__(self, path_or_stream: Union[BytesIO, Path]):
         super().__init__(path_or_stream)
         self._pdoc = pdfium.PdfDocument(path_or_stream)
         # Parsing cells with docling_parser call
-        print("PARSING WITH DOCLING PARSE")
+        if isinstance(path_or_stream, BytesIO):
+            raise NotImplemented("This backend does not support byte streams yet.")
         parser = pdf_parser()
         self._parser_doc = parser.find_cells(str(path_or_stream))
 
diff --git a/docling/backend/pypdfium2_backend.py b/docling/backend/pypdfium2_backend.py
index f2272d5..e5540f4 100644
--- a/docling/backend/pypdfium2_backend.py
+++ b/docling/backend/pypdfium2_backend.py
@@ -199,7 +199,7 @@ class PyPdfiumPageBackend(PdfPageBackend):
 
 
 class PyPdfiumDocumentBackend(PdfDocumentBackend):
-    def __init__(self, path_or_stream: Iterable[Union[BytesIO, Path]]):
+    def __init__(self, path_or_stream: Union[BytesIO, Path]):
         super().__init__(path_or_stream)
         self._pdoc = pdfium.PdfDocument(path_or_stream)