diff --git a/pysindy/optimizers/stable_linear_sr3.py b/pysindy/optimizers/stable_linear_sr3.py
index fd1cdd704..106e784b6 100644
--- a/pysindy/optimizers/stable_linear_sr3.py
+++ b/pysindy/optimizers/stable_linear_sr3.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import warnings
 from typing import Tuple
 
@@ -205,7 +207,7 @@ def _create_var_and_part_cost(
         y: np.ndarray,
         coef_sparse: np.ndarray,
         coef_neg_def: np.ndarray,
-    ) -> Tuple[cp.Variable, cp.Expression]:
+    ) -> Tuple["cp.Variable", "cp.Expression"]:
         xi = cp.Variable(coef_sparse.shape[0] * coef_sparse.shape[1])
         cost = cp.sum_squares(x @ xi - y.flatten())
         cost = cost + cp.sum_squares(xi - coef_neg_def.flatten()) / (2 * self.nu)