Add types.

src/data_flow/nifti_operations.py

@@ -28,9 +28,9 @@ def read_nii(filepath: Union[str, Path]) -> Tuple[np.ndarray, np.ndarray]:
 
     Returns
     -------
-    image : TYPE
+    image : np.ndarray
         Image data.
-    affine_matrix : TYPE
+    affine_matrix : np.ndarray
         Corresponsing affine matrix.
 
     """
@@ -120,7 +120,7 @@ def convert_to_original_datatype(
 
     Returns
     -------
-    image : TYPE
+    image : np.ndarray
         Converted image.
 
     """