docs: def _tls_encrypt(alg, p):
      """
      Provided with an already MACed TLSCompressed packet, and a stream or block
      cipher alg, the function converts it into a TLSCiphertext (i.e. encrypts it
      and updates length). The function returns a newly created TLSCiphertext
      instance.
      """
      c = TLSCiphertext()
      c.type = p.type
      c.version = p.version
      c.data = alg.encrypt(p.data)
      c.len = len(c.data)
      return c