PHPCS PSR2 standard with var_dump disallowed

composer.json

{
    "require": {

    },
    "require-dev": {
        "squizlabs/php_codesniffer": "2.*@dev"
    }
}

PHPCS-PSR2-standard-with-var_dump-disallowed

ruleset.xml

<?xml version="1.0"?>
<ruleset name="Custom Standard">
    <description>A little bit extended PSR2 standard</description>

    <exclude-pattern>*/tests/*</exclude-pattern>
    <exclude-pattern>*/data/*</exclude-pattern>

    <rule ref="PSR2"/>

    <rule ref="Squiz.PHP.ForbiddenFunctions">
        <properties>
            <property name="forbiddenFunctions" type="array" value="var_dump=>NULL,sizeof=>count,delete=>unset,print=>echo,is_null=>NULL,create_function=>NULL"/>
        </properties>
    </rule>

</ruleset>

test.php

<?php

var_dump('x');

sizoef 'asdf';

delete $x;

print 'asdf';

is_null(null);