Have I used is_email() correctly for this email field?

Hello,

I’m building my first widget. I need to add an email field to my widget, is this correct please? Should I use is_email() ?

function update($new_instance, $old_instance) {
     $instance = $old_instance;
     $instance['email'] = is_email($new_instance['email']);

    return $instance;
     }

And

function form($instance) {

     $email = sanitize_email($instance['email']);
          ?>

 <p>
    <label for="<?php echo  $this->get_field_id('email'); ?>">
     <?php _e('Email'); ?>  </label>
     <input class="widefat" id="<?php echo $this->get_field_id('email'); ?>" name="<?php echo $this->get_field_name('email'); ?>" type="email" value="<?php echo $email; ?> " />
    </p>
    <?php
    }

Please can someone advise? I would really appreciate some help. Thanks