Remove union shorthand

test/contrib/hsgp/test_approximation.py

@@ -5,7 +5,7 @@
 
 from functools import reduce
 from operator import mul
-from typing import Literal
+from typing import Literal, Union
 
 import numpy as np
 import pytest
@@ -117,7 +117,11 @@ def synthetic_two_dim_data() -> tuple[ArrayImpl, ArrayImpl]:
     ],
 )
 def test_kernel_approx_squared_exponential(
-    x1: ArrayImpl, x2: ArrayImpl, length: float | ArrayImpl, ell: float, xfail: bool
+    x1: ArrayImpl,
+    x2: ArrayImpl,
+    length: Union[float, ArrayImpl],
+    ell: float,
+    xfail: bool,
 ):
     """ensure that the approximation of the squared exponential kernel is accurate,
     matching the exact kernel implementation from sklearn.
@@ -140,7 +144,7 @@ def test_kernel_approx_squared_exponential(
     def _exact_rbf(length):
         return RBF(length)(x1, x2).squeeze(axis=-1)
 
-    if isinstance(length, float | int):
+    if isinstance(length, Union[float, int]):
         exact = _exact_rbf(length)
     elif length.ndim == 1:
         exact = _exact_rbf(length)
@@ -218,7 +222,7 @@ def test_kernel_approx_squared_matern(
     def _exact_matern(length):
         return Matern(length_scale=length, nu=nu)(x1, x2).squeeze(axis=-1)
 
-    if isinstance(length, float | int):
+    if isinstance(length, Union[float, int]):
         exact = _exact_matern(length)
     elif length.ndim == 1:
         exact = _exact_matern(length)
@@ -280,8 +284,8 @@ def test_approximation_squared_exponential(
     x: ArrayImpl,
     alpha: float,
     length: float,
-    ell: int | float | list[int | float],
-    m: int | list[int],
+    ell: Union[int, float, list[Union[int, float]]],
+    m: Union[int, list[int]],
     non_centered: bool,
 ):
     def model(x, alpha, length, ell, m, non_centered):
@@ -332,8 +336,8 @@ def test_approximation_matern(
     nu: float,
     alpha: float,
     length: float,
-    ell: int | float | list[int | float],
-    m: int | list[int],
+    ell: Union[int, float, list[Union[int, float]]],
+    m: Union[int, list[int]],
     non_centered: bool,
 ):
     def model(x, nu, alpha, length, ell, m, non_centered):
@@ -375,8 +379,8 @@ def model(x, nu, alpha, length, ell, m, non_centered):
 def test_squared_exponential_gp_model(
     synthetic_one_dim_data,
     synthetic_two_dim_data,
-    ell: float | int | list[float | int],
-    m: int | list[int],
+    ell: Union[float, int, list[Union[float, int]]],
+    m: Union[int, list[int]],
     non_centered: bool,
     num_dim: Literal[1, 2],
 ):
@@ -433,8 +437,8 @@ def test_matern_gp_model(
     synthetic_one_dim_data,
     synthetic_two_dim_data,
     nu: float,
-    ell: int | float | list[float | int],
-    m: int | list[int],
+    ell: Union[int, float, list[Union[float, int]]],
+    m: Union[int, list[int]],
     non_centered: bool,
     num_dim: Literal[1, 2],
 ):