[BugFix] Fix 'npu' attribute (#3159)

Author: vmoens

torchrl/collectors/collectors.py

@@ -733,7 +733,7 @@ def __init__(
             elif torch.backends.mps.is_available() and hasattr(torch, "mps"):
                 # Will break for older PT versions which don't have torch.mps
                 self._sync_storage = torch.mps.synchronize
-            elif torch.npu.is_available() and hasattr(torch, "npu"):
+            elif hasattr(torch, "npu") and torch.npu.is_available():
                 self._sync_storage = torch.npu.synchronize
             elif self.storing_device.type == "cpu":
                 self._sync_storage = _do_nothing
@@ -749,7 +749,7 @@ def __init__(
                 self._sync_env = torch.cuda.synchronize
             elif torch.backends.mps.is_available() and hasattr(torch, "mps"):
                 self._sync_env = torch.mps.synchronize
-            elif torch.npu.is_available() and hasattr(torch, "npu"):
+            elif hasattr(torch, "npu") and torch.npu.is_available():
                 self._sync_env = torch.npu.synchronize
             elif self.env_device.type == "cpu":
                 self._sync_env = _do_nothing
@@ -764,7 +764,7 @@ def __init__(
                 self._sync_policy = torch.cuda.synchronize
             elif torch.backends.mps.is_available() and hasattr(torch, "mps"):
                 self._sync_policy = torch.mps.synchronize
-            elif torch.npu.is_available() and hasattr(torch, "npu"):
+            elif hasattr(torch, "npu") and torch.npu.is_available():
                 self._sync_policy = torch.npu.synchronize
             elif self.policy_device.type == "cpu":
                 self._sync_policy = _do_nothing