我尝试创建一个新类，该类包含一个创建短代码的操作，该短代码位于我的站点上，但似乎不起作用。谁能告诉我哪里出了问题？

该类是在其自己的PHP文件中编写的，该文件位于site\\URL/includes/frontend。登记表。php

Dreamweaver没有抛出任何语法错误？

    <?php



class RegistrationForm {

    function __construct (){
        $this->make_shortcode();
    }

    function make_shortcode (){
        add_shortcode (\'Show Form\', array($this, \'form_generate\'));
    }

    function form_generate () {

        ob_start(); ?>

            <form class="form-horizontal">
                <fieldset>

                <!-- Form Name -->
                <legend>Form Name</legend>

                <!-- Text input-->
                <div class="form-group">
                  <label class="col-md-4 control-label" for="textinput">Name</label>  
                  <div class="col-md-4">
                  <input id="textinput" name="textinput" type="text" placeholder="Name" class="form-control input-md" required="">

                  </div>
                </div>

                <!-- Text input-->
                <div class="form-group">
                  <label class="col-md-4 control-label" for="textinput">Email Address</label>  
                  <div class="col-md-4">
                  <input id="textinput" name="textinput" type="text" placeholder="Email" class="form-control input-md" required="">

                  </div>
                </div>

                <!-- Password input-->
                <div class="form-group">
                  <label class="col-md-4 control-label" for="passwordinput">Password</label>
                  <div class="col-md-4">
                    <input id="passwordinput" name="passwordinput" type="password" placeholder="Password" class="form-control input-md" required="">

                  </div>
                </div>

                <!-- Text input-->
                <div class="form-group">
                  <label class="col-md-4 control-label" for="textinput">Store Name</label>  
                  <div class="col-md-4">
                  <input id="textinput" name="textinput" type="text" placeholder="Store Name" class="form-control input-md" required="">

                  </div>
                </div>

                </fieldset>
            </form>

    <?php $output = ob_clean();
    return ($output);

    }

} /*END OF CLASS*/

$new_form = new RegistrationForm;
return ($new_form);

?>