code: def cmd_signing(self, args):
          '''handle link commands'''
          usage = "signing: <setup|remove|disable|key> passphrase"
          if len(args) == 0:
              print(usage)
          elif args[0] == 'setup':
              self.cmd_signing_setup(args[1:])
          elif args[0] == 'key':
              self.cmd_signing_key(args[1:])
          elif args[0] == 'disable':
              self.cmd_signing_disable(args[1:])
          elif args[0] == 'remove':
              self.cmd_signing_remove(args[1:])
          else:
              print(usagef cmd_signing(self, args):
          '''handle link commands'''
          usage = "signing: <setup|remove|disable|key> passphrase"
          if len(args) == 0:
              print(usage)
          elif args[0] == 'setup':
              self.cmd_signing_setup(args[1:])
          elif args[0] == 'key':
              self.cmd_signing_key(args[1:])
          elif args[0] == 'disable':
              self.cmd_signing_disable(args[1:])
          elif args[0] == 'remove':
              self.cmd_signing_remove(args[1:])
          else:
              print(usage)
docs: handle link commands