code: def list(self):
          
          response = self._client.raw('disk.list', {})
  
          result = response.get()
  
          if result.state != 'SUCCESS':
              raise RuntimeError('failed to list disks: %s' % result.stderr)
  
          if result.level != 20:  # 20 is JSON output.
              raise RuntimeError('invalid response type from disk.list command')
  
          data = result.data.strip()
          if data:
              return json.loads(data)
          else:
              return {}
docs: List available block devices