docs: def should_add_ServerHello(self):
          """
          Selecting a cipher suite should be no trouble as we already caught
          the None case previously.
  
          Also, we do not manage extensions at all.
          """
          if isinstance(self.mykey, PrivKeyRSA):
              kx = "RSA"
          elif isinstance(self.mykey, PrivKeyECDSA):
              kx = "ECDSA"
          usable_suites = get_usable_ciphersuites(self.cur_pkt.ciphers, kx)
          c = usable_suites[0]
          if self.preferred_ciphersuite in usable_suites:
              c = self.preferred_ciphersuite
          self.add_msg(TLSServerHello(cipher=c))
          raise self.ADDED_SERVERHELLO()