docs: function addScope (scope) {
    if (!scope) {
      return
    }
    var oldScope = new Set(this.scope.split(' '))
    var newScope
    // Convert the incoming new scopes to a Set
    if (typeof scope === 'string') {
      newScope = new Set(scope.split(' '))
    } else if (Array.isArray(scope)) {
      newScope = new Set(scope)
    } else {
      throw new RangeError('Trying to add an invalid scope object')
    }
    oldScope.forEach(function (item) {
      newScope.add(item)
    })
    // Convert back to string
    this.scope = Array.from(newScope).join(' ')
  }