code: function activitiesUrl(workspaceSid, activitySid) {
    return _.join(
      _.filter([workspacesUrl(workspaceSid), 'Activities', activitySid], _.isString),
      '/'
    );
  }
docs: Generate TaskRouter activity url
  
  @param {string} workspaceSid workspace sid
  @param {string} [activitySid] activity sid or '**' for all activities
  @returns {string} generated url