instance method method_missing

# File actionpack/lib/action_controller/metal/strong_parameters.rb, line 781
    def method_missing(method_sym, *args, &block)
      if @parameters.respond_to?(method_sym)
        message = <<-DEPRECATE.squish
          Method #{method_sym} is deprecated and will be removed in Rails 5.1,
          as `ActionController::Parameters` no longer inherits from
          hash. Using this deprecated behavior exposes potential security
          problems. If you continue to use this method you may be creating
          a security vulnerability in your app that can be exploited. Instead,
          consider using one of these documented methods which are not
          deprecated: http://api.rubyonrails.org/v#{ActionPack.version}/classes/ActionController/Parameters.html
        DEPRECATE
        ActiveSupport::Deprecation.warn(message)
        @parameters.public_send(method_sym, *args, &block)
      else
        super
      end
    end