code: def to_disk_indices(value):
      
      ret = []
      p = re.compile(r'Bus\s+(\w+)\s+Enclosure\s+(\w+)\s+Disk\s+(\w+)')
      if value is not None:
          for line in value.split('\n'):
              line = line.strip()
              if len(line) == 0:
                  continue
              matched = re.search(p, line)
              if matched is None or len(matched.groups()) < 3:
                  continue
              else:
                  ret.append('{}_{}_{}'.format(*matched.groups()))
      return ret
docs: Convert following input to disk indices
  
      Sample input:
  
      ```
      Disks:
      Bus 0 Enclosure 0 Disk 9
      Bus 1 Enclosure 0 Disk 12
      Bus 1 Enclosure 0 Disk 9
      Bus 0 Enclosure 0 Disk 4
      Bus 0 Enclosure 0 Disk 7
      ```
  
      :param value: disk list
      :return: disk indices in list