class Psych::Visitors::RestrictedYAMLTree

def initialize emitter, ss, options
  super
  @permitted_classes = DEFAULT_PERMITTED_CLASSES.dup
  Array(options[:permitted_classes]).each do |klass|
    @permitted_classes[klass] = true
  end
  @permitted_symbols = {}.compare_by_identity
  Array(options[:permitted_symbols]).each do |symbol|
    @permitted_symbols[symbol] = true
  end
  @aliases = options.fetch(:aliases, false)
end