diff --git a/rl4co/models/zoo/gfacs/model.py b/rl4co/models/zoo/gfacs/model.py
index a2dbfdba..fd92052d 100644
--- a/rl4co/models/zoo/gfacs/model.py
+++ b/rl4co/models/zoo/gfacs/model.py
@@ -110,18 +110,17 @@ def calculate_loss(
         return tb_loss
 
     def calculate_log_pb_uniform(self, actions: torch.Tensor, n_ants: int):
-        match self.env.name:
-            case "tsp":
-                return math.log(1 / 2 * actions.size(1))
-            case "cvrp":
-                _a1 = actions.detach().cpu().numpy()
-                # shape: (batch, max_tour_length)
-                n_nodes = np.count_nonzero(_a1, axis=1)
-                _a2 = _a1[:, 1:] - _a1[:, :-1]
-                n_routes = np.count_nonzero(_a2, axis=1) - n_nodes
-                _a3 = _a1[:, 2:] - _a1[:, :-2]
-                n_multinode_routes = np.count_nonzero(_a3, axis=1) - n_nodes
-                log_b_p = - scipy.special.gammaln(n_routes + 1) - n_multinode_routes * math.log(2)
-                return unbatchify(torch.from_numpy(log_b_p).to(actions.device), n_ants)
-            case _:
-                raise ValueError(f"Unknown environment: {self.env.name}")
+        if self.env.name == "tsp":
+            return math.log(1 / 2 * actions.size(1))
+        elif self.env.name == "cvrp":
+            _a1 = actions.detach().cpu().numpy()
+            # shape: (batch, max_tour_length)
+            n_nodes = np.count_nonzero(_a1, axis=1)
+            _a2 = _a1[:, 1:] - _a1[:, :-1]
+            n_routes = np.count_nonzero(_a2, axis=1) - n_nodes
+            _a3 = _a1[:, 2:] - _a1[:, :-2]
+            n_multinode_routes = np.count_nonzero(_a3, axis=1) - n_nodes
+            log_b_p = - scipy.special.gammaln(n_routes + 1) - n_multinode_routes * math.log(2)
+            return unbatchify(torch.from_numpy(log_b_p).to(actions.device), n_ants)
+        else:
+            raise ValueError(f"Unknown environment: {self.env.name}")