code: def command_ls(self, list_what):
          
          if list_what in ('available', 'mounted', 'unmounted'):
              callback = getattr(self.environment, 'get_%s_ids' % list_what)
              lst = callback()
          else:
              lst = []
          if len(lst) != 0:
              print(("\n".join(lst)))
docs: Lists the available/mounted/unmounted sftp systems.
          Usage: sftpman ls {what}
          Where {what} is one of: available, mounted, unmounted