Hi

I'm trying to create an addon to print pdf product sheet from products. With this minimal example, the entry 'Product sheet' appears on the 'Print' menu, but when clicked it displays the following error:

Bad Request
The browser (or proxy) sent a request that this server could not understand.
KeyError: 'Content-Disposition'

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data>
        <report
            id="report_product_template_sheet"
            string="Product sheet"
            model="product.template"
            report_type="qweb-pdf"
            name="my_addon.report_producttemplatesheet"
            file="my_addon.report_producttemplatesheet"
            />

        <template id="report_producttemplatesheet">
            <t t-call="web.html_container">
                <div class="page">
                    <h1>Hi</h1>
                </div>
            </t>
        </template>
    </data>
</odoo>

I'm using Odoo 10 Community on Debian.

Thanks in advance