def respond_to_missing?(method_name, include_private = false)
      observer.respond_to?(method_name.to_sym) ||
        env.aliases.include?(method_name.to_sym) || super
    end
def respond_to_missing?(method_name, include_private = false)
      observer.respond_to?(method_name.to_sym) ||
        env.aliases.include?(method_name.to_sym) || super
    end
Test if a message can be handled by state machine

 @param [String] method_name

 @param [Boolean] include_private

 @return [Boolean]

 @api private