diff --git a/pyzx/tensor.py b/pyzx/tensor.py
index 81a23b96..37b4edef 100644
--- a/pyzx/tensor.py
+++ b/pyzx/tensor.py
@@ -132,25 +132,25 @@ def tensorfy(g: 'BaseGraph[VT,ET]', preserve_scalar:bool=True) -> np.ndarray:
             neigh = list(g.neighbors(v))
             d = len(neigh)
             if v in inputs:
-                if types[v] != 0: raise ValueError("Wrong type for input:", v, types[v])
+                if types[v] != VertexType.BOUNDARY: raise ValueError("Wrong type for input:", v, types[v])
                 continue # inputs already taken care of
             if v in outputs:
                 if d != 1: raise ValueError("Weird output")
-                if types[v] != 0: raise ValueError("Wrong type for output:",v, types[v])
+                if types[v] != VertexType.BOUNDARY: raise ValueError("Wrong type for output:",v, types[v])
                 d += 1
                 t = id2
             else:
                 phase = pi*phases[v]
-                if types[v] == 1:
+                if types[v] == VertexType.Z:
                     t = Z_to_tensor(d,phase)
-                elif types[v] == 2:
+                elif types[v] == VertexType.X:
                     t = X_to_tensor(d,phase)
-                elif types[v] == 3:
+                elif types[v] == VertexType.H_BOX:
                     t = H_to_tensor(d,phase)
-                elif types[v] == 4 or types[v] == 5:
+                elif types[v] == VertexType.W_INPUT or types[v] == VertexType.W_OUTPUT:
                     if phase != 0: raise ValueError("Phase on W node")
                     t = W_to_tensor(d)
-                elif types[v] == 6:
+                elif types[v] == VertexType.Z_BOX:
                     if phase != 0: raise ValueError("Phase on Z box")
                     label = get_z_box_label(g, v)
                     t = Z_box_to_tensor(d, label)