set crf as optional

Author: Dan-Flores

src/torchcodec/encoders/_video_encoder.py

@@ -1,5 +1,5 @@
 from pathlib import Path
-from typing import Union
+from typing import Optional, Union
 
 import torch
 from torch import Tensor
@@ -36,7 +36,7 @@ def to_file(
         self,
         dest: Union[str, Path],
         *,
-        crf: int = None,
+        crf: Optional[int] = None,
     ) -> None:
         """Encode frames into a file.
 
@@ -59,7 +59,7 @@ def to_tensor(
         self,
         format: str,
         *,
-        crf: int = None,
+        crf: Optional[int] = None,
     ) -> Tensor:
         """Encode frames into raw bytes, as a 1D uint8 Tensor.
 
@@ -85,7 +85,7 @@ def to_file_like(
         file_like,
         format: str,
         *,
-        crf: int = None,
+        crf: Optional[int] = None,
     ) -> None:
         """Encode frames into a file-like object.