code: function LinkedinTokenStrategy(options, verify) {
    options = options || {}
    options.authorizationURL = options.authorizationURL || 'https://www.linkedin.com';
    options.tokenURL = options.tokenURL || 'https://www.linkedin.com/uas/oauth2/accessToken';
    options.scopeSeparator = options.scopeSeparator || ',';
  
    this._passReqToCallback = options.passReqToCallback;
  
    OAuth2Strategy.call(this, options, verify);
    this.profileUrl = options.profileURL || 'https://api.linkedin.com/v1/people/~:(id,first-name,last-name,email-address,public-profile-url)?format=json';
    this.name = 'linkedin-token';
  }
docs: `LinkedinTokenStrategy` constructor.
  
  The Linkedin authentication strategy authenticates requests by delegating to
  Linkedin using the OAuth 2.0 protocol.
  
  And accepts only access_tokens. Specialy designed for client-side flow (implicit grant flow)
  
  Applications must supply a `verify` callback which accepts an `accessToken`,
  `refreshToken` and service-specific `profile`, and then calls the `done`
  callback supplying a `user`, which should be set to `false` if the
  credentials are not valid.  If an exception occured, `err` should be set.
  
  Options:
  - `clientID`      your Linkedin application's App ID
  - `clientSecret`  your Linkedin application's App Secret
  
  Examples:
  
  passport.use(new LinkedinTokenStrategy({
  clientID: '123-456-789',
  clientSecret: 'shhh-its-a-secret'
  },
  function(accessToken, refreshToken, profile, done) {
  User.findOrCreate(..., function (err, user) {
  done(err, user);
  });
  }
  ));
  
  @param {Object} options
  @param {Function} verify
  @api public