remove parallel_devices

Author: DuYicong515

CHANGELOG.md

@@ -719,6 +719,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - Removed `AcceleratorConnector.parallel_device_ids` property ([#12072](https://github.com/PyTorchLightning/pytorch-lightning/pull/12072))
 
 
+- Removed `AcceleratorConnector.parallel_devices` property ([#12075](https://github.com/PyTorchLightning/pytorch-lightning/pull/12075))
+
+
 ### Fixed
 
 - Fixed an issue where `ModelCheckpoint` could delete older checkpoints when `dirpath` has changed during resumed training ([#12045](https://github.com/PyTorchLightning/pytorch-lightning/pull/12045))

pytorch_lightning/trainer/connectors/accelerator_connector.py

@@ -780,10 +780,6 @@ def _lazy_init_strategy(self) -> None:
     of accessing this information through the strategy/accelerator directly."""
     # TODO: deprecate all properties below
 
-    @property
-    def parallel_devices(self) -> List[Union[torch.device, int]]:
-        return self._parallel_devices
-
     @property
     def num_processes(self) -> int:
         return self.devices if self.devices is not None else 1