code: def length(ext_id, ext_des, ext_src):
          # type: (bytes, bytes, bytes) -> int
          '''
          Static method to return the length of the Rock Ridge Extensions Reference
          record.
  
          Parameters:
           ext_id - The extension identifier to use.
           ext_des - The extension descriptor to use.
           ext_src - The extension specification source to use.
          Returns:
           The length of this record in bytes.
          '''
          return 8 + len(ext_id) + len(ext_des) + len(ext_srcf length(ext_id, ext_des, ext_src):
          # type: (bytes, bytes, bytes) -> int
          '''
          Static method to return the length of the Rock Ridge Extensions Reference
          record.
  
          Parameters:
           ext_id - The extension identifier to use.
           ext_des - The extension descriptor to use.
           ext_src - The extension specification source to use.
          Returns:
           The length of this record in bytes.
          '''
          return 8 + len(ext_id) + len(ext_des) + len(ext_src)
docs: Static method to return the length of the Rock Ridge Extensions Reference
          record.
  
          Parameters:
           ext_id - The extension identifier to use.
           ext_des - The extension descriptor to use.
           ext_src - The extension specification source to use.
          Returns:
           The length of this record in bytes.