code: def cmd_signing_key(self, args):
          '''set signing key on connection'''
          if len(args) == 0:
              print("usage: signing setup passphrase")
              return
          if not self.master.mavlink20():
              print("You must be using MAVLink2 for signing")
              return
          passphrase = args[0]
          key = self.passphrase_to_key(passphrase)
          self.master.setup_signing(key, sign_outgoing=True, allow_unsigned_callback=self.allow_unsigned)
          print("Setup signing key"f cmd_signing_key(self, args):
          '''set signing key on connection'''
          if len(args) == 0:
              print("usage: signing setup passphrase")
              return
          if not self.master.mavlink20():
              print("You must be using MAVLink2 for signing")
              return
          passphrase = args[0]
          key = self.passphrase_to_key(passphrase)
          self.master.setup_signing(key, sign_outgoing=True, allow_unsigned_callback=self.allow_unsigned)
          print("Setup signing key")
docs: set signing key on connection