In openerp render function returns the 'ir.ui.view' but embellish it with some variables/methods used in reports. param values is additional methods/variables used in the rendering returns is html representation of the template.
use this code show below in .py file,

def render(self, cr, uid, ids, template, values=None, context=None):

        if values is None:
            values = {}

        if context is None:
            context = {}

        context = dict(context, inherit_branding=True)  # Tell QWeb to brand the generated html

        view_obj = self.pool['ir.ui.view']

        user = self.pool['res.users'].browse(cr, uid, uid)
        website = None
        if request and hasattr(request, 'website'):
            if request.website is not None:
                website = request.website
                context = dict(context, translatable=context.get('lang') != request.website.default_lang_code)

        values.update(
            time=time,
            context_timestamp=lambda t: fields.datetime.context_timestamp(cr, uid, t, context),
            editable=True,
            user=user,
            res_company=user.company_id,
            website=website,
        )
        return view_obj.render(cr, uid, template, values, context=context)