From c5571459bcd91296bd4081801abc2c73a3407642 Mon Sep 17 00:00:00 2001
From: alessiamarcolini <98marcolini@gmail.com>
Date: Mon, 23 Aug 2021 21:47:49 +0200
Subject: [PATCH] Add message to exception

---
 src/histolab/filters/compositions.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/histolab/filters/compositions.py b/src/histolab/filters/compositions.py
index 0ded8192..367030e1 100644
--- a/src/histolab/filters/compositions.py
+++ b/src/histolab/filters/compositions.py
@@ -97,7 +97,7 @@ def tissue_mask_filters(self) -> imf.Compose:
             - `morphological_filters.BinaryFillHoles(structure=np.ones((5, 5)))
               <morphological_filters.html#src.histolab.filters.morphological_filters.BinaryFillHoles>`_
         """
-        raise NotImplementedError
+        raise NotImplementedError("Must be implemented by each subclass")
 
 
 class _SlideFiltersComposition(FiltersComposition):