diff --git a/mattport/nerf/graph/vanilla_nerf.py b/mattport/nerf/graph/vanilla_nerf.py
index 61cee7b18..074551120 100644
--- a/mattport/nerf/graph/vanilla_nerf.py
+++ b/mattport/nerf/graph/vanilla_nerf.py
@@ -24,7 +24,7 @@ from mattport.structures.rays import RaySamples
 class NeRFField(nn.Module):
     """NeRF module"""
 
-    def __init__(self, num_layers=8, layer_width=256, skip_connections: Tuple = (4)) -> None:
+    def __init__(self, num_layers=8, layer_width=256, skip_connections: Tuple = (4,)) -> None:
         super().__init__()
         self.num_layers = num_layers
         self.layer_width = layer_width