code: def available_memory(self, device_index=None):
      return self.total_memory(device_index) - self.memory_allocated(
          device_index
      )
  
imports: import importlib
  import inspect
  from .abstract_accelerator import DeepSpeedAccelerator
label_desc: Use image node_id 34 for calling the NPU_Accelerator obj's underlying member method code with example usage: obj.available_memory(device_index) and returns: unknown