Update node.py (#196)

Author: TeunHuijben

Diff for: ultrack/core/segmentation/node.py

@@ -328,7 +328,7 @@ def from_mask(
 
         node.bbox = bbox
         node.mask = mask
-        node.area = mask.sum()
+        node.area = int(mask.sum())
         node.centroid = node._centroid()
 
         return node