Someone please help me with render_qweb_pdf() from Odoo. I am a beginner in odoo as well as in XML,

My python code

@api.model
    def print_invoice(self):
        x = 'pawan'
        y = 18
        report = {
            "report": {
                "name": x,
                "roll": y
            }
        }
        # import pdb; pdb.set_trace()
        xx = self.env.ref('fnf_stock.stock_pdf').sudo(
        ).render_qweb_pdf(self.id, report)

        return xx

My XML code
<template id="stock_picking" name="stock_picking">
        <t t-call="web.html_container">
            <t t-as="o" t-foreach="docs">
                <!-- article class is very important to display content -->
                <div class="article">
                    <div class="row">
                            <t t-esc="report['name']"/>
                            <t t-esc="report['roll']"/>
                    </div>
                </div>
            </t>
        </t>
    </template>