code: def _is_device_active(device):
          
          cmd = ['dmsetup', 'info', device]
          dmsetup_info = util.subp(cmd)
          for dm_line in dmsetup_info.stdout.split("\n"):
              line = dm_line.split(':')
              if ('State' in line[0].strip()) and ('ACTIVE' in line[1].strip()):
                  return True
          return False
docs: Checks dmsetup to see if a device is already active