fix setup.py again

setup.py

@@ -9,13 +9,13 @@
 
 
 # If WITH_CUDA is defined
-if os.getenv("WITH_CUDA") is None:
-    if os.environ.get("WITH_CUDA", "0") == "1":
-        use_cuda = True
-    elif os.environ.get("WITH_CUDA", "0") == "0":
-        use_cuda = False
-    else:
-        raise ValueError("Invalid flag with WITH_CUDA environment variable. Expected '0' or '1'")
+env_with_cuda = os.getenv("WITH_CUDA")
+if env_with_cuda is not None:
+    if env_with_cuda not in ("0", "1"):
+        raise ValueError(
+            "Invalid flag with WITH_CUDA environment variable. Expected '0' or '1'"
+        )
+    use_cuda = env_with_cuda == "1"
 else:
     use_cuda = torch.cuda._is_compiled()