purchase_print_report/views/template.xml

<openerp>
    <data>
        <!-- <template id="sale_print_report.assets" name="Eiru Assets" inherit_id="web.assets_backend">
            <xpath expr="." position="inside">
                <script type="text/javascript" src="/sale_print_report/static/src/sale.js" />
            </xpath>
        </template> -->

        <template id="purchase_print_report.assets_backend" name="purchase_print_voucher_assets" inherit_id="eiru_assets.assets">
            <xpath expr="." position="inside">
                <link rel="stylesheet" href="/purchase_print_report/static/src/css/style.css"/>
                <script type="text/javascript" src="/purchase_print_report/static/src/js/purchase.js"/>
            </xpath>
        </template>
    </data>
</openerp>