code: def get_hmac(self, password):
          
          salt = current_app.config.SECURITY_PASSWORD_SALT
  
          if salt is None:
              raise RuntimeError(
                  'The configuration value `SECURITY_PASSWORD_SALT` must '
                  'not be None when the value of `SECURITY_PASSWORD_HASH` is '
                  'set to "%s"' % self.security.password_hash)
  
          h = hmac.new(encode_string(salt), encode_string(password), hashlib.sha512)
          return base64.b64encode(h.digest())
docs: Returns a Base64 encoded HMAC+SHA512 of the password signed with
          the salt specified by ``SECURITY_PASSWORD_SALT``.
  
          :param password: The password to sign.