code: def have_key(self, *keygrips):
          
          for keygrip in keygrips:
              try:
                  self.get_identity(keygrip=keygrip)
                  break
              except KeyError as e:
                  log.warning('HAVEKEY(%s) failed: %s', keygrip, e)
          else:
              raise AgentError(b'ERR 67108881 No secret key <GPG Agent>')
docs: Check if any keygrip corresponds to a TREZOR-based key.