docs: def _update_sig(self, m, key):
          """
          Sign 'm' with the PrivKey 'key' and update our own 'sig_val'.
          Note that, even when 'sig_alg' is not None, we use the signature scheme
          of the PrivKey (neither do we care to compare the both of them).
          """
          if self.sig_alg is None:
              if self.tls_session.tls_version >= 0x0300:
                  self.sig_val = key.sign(m, t='pkcs', h='md5-sha1')
              else:
                  self.sig_val = key.sign(m, t='pkcs', h='md5')
          else:
              h, sig = _tls_hash_sig[self.sig_alg].split('+')
              if sig.endswith('pss'):
                  t = "pss"
              else:
                  t = "pkcs"
              self.sig_val = key.sign(m, t=t, h=h)