build: remove typing_extensions

environment.yml

@@ -9,4 +9,3 @@ dependencies:
   - scikit-learn>=1.0.0,<2.0.0
   - pyjuliacall>=0.9.15,<0.10.0
   - click>=7.0.0,<9.0.0
-  - typing_extensions>=4.0.0,<5.0.0

pysr/sr.py

@@ -12,12 +12,7 @@ from datetime import datetime
 from io import StringIO
 from multiprocessing import cpu_count
 from pathlib import Path
-from typing import Callable, Dict, List, Optional, Tuple, Union
-
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
+from typing import Callable, Dict, List, Literal, Optional, Tuple, Union, cast
 
 import numpy as np
 import pandas as pd

requirements.txt

@@ -5,4 +5,3 @@ scikit_learn>=1.0.0,<2.0.0
 juliacall==0.9.20
 click>=7.0.0,<9.0.0
 setuptools>=50.0.0
-typing_extensions>=4.0.0,<5.0.0; python_version < "3.8"