PHP Decode

<?php

/** @phpstub */
class Normalizer
{
    const FORM_C = NULL;
    const FORM_D = NULL;
    const FORM_KC = NULL;
    const FORM_KD = NULL;
    const NONE = NULL;
    const OPTION_DEFAULT = NULL;

    /**
     * 
       Checks if the provided string is already in the specified normalization
       form.
      
     *
     * @param string $input
     * @param string $form
     * @param string $input
     * @param string $form
     *
     * @return bool true if normalized, false otherwise or if there an error
     */
    public function isNormalized($input, $form = 'Normalizer::FORM_C', $input, $form = 'Normalizer::FORM_C')
    {
    }

    /**
     * 
       Normalizes the input provided and returns the normalized string
      
     *
     * @param string $input
     * @param string $form
     * @param string $input
     * @param string $form
     *
     * @return string The normalized string or null if an error occurred.
     */
    public function normalize($input, $form = 'Normalizer::FORM_C', $input, $form = 'Normalizer::FORM_C')
    {
    }
} ?>