function generateAccessToken(userId, scope, sessionId, jwtSecret) {
  return jwt.sign({ user_id: userId, scope, session_id: sessionId }, jwtSecret, {
    algorithm: 'HS256',
    audience: 'user',
    issuer: 'gladys',
    expiresIn: ACCESS_TOKEN_VALIDITY,
  });
}
@private
@description Generate an access token token.
@param {string} userId - The UserId.
@param {Array} scope - The scope.
@param {string} sessionId - The session ID.
@param {string} jwtSecret - JWT secret.
@example
const accessToken = generateAccessToken(
 '31a4d8d9-bf39-49be-8588-dac2b8cfa74a',
 ['dashboard:write', 'dashboard:read'],
 '2a2ccdbd-88ff-42a6-a7de-b98cb0cb3b20',
 'secret'
);
@returns {string} Return accessToken.