Hello, i want create custom report with my custom renderer, i am using Odoo v9 community. I have error message when generating report:

QWebException: "'NoneType' object is not callable" while evaluating
"translate_doc(doc_id, doc_model, 'partner_id.lang', 'custom_module_name.report_object_review_document')"

my custom_module_name_report.xml:

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <report
            string="Object review"
            id="action_report_object_review"
            model="crm.lead"
            report_type="qweb-pdf"
            name="custom_module_name.report_object_review"
            file="custom_module_name.report_object_review"
        />
    </data>
</openerp>

report_object_review.xml:

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <template id="report_object_review_document">
        <t t-foreach="docs" t-as="o">
            </div>
                <div class="page">
                    <div class="row">
                    <h3>Title</h3>
                    <span t-esc="get_format()"/>
                    </div>
                </div>
            </t>
        </template>
        <template id="report_object_review">
            <t t-call="report.html_container">
                <t t-foreach="doc_ids" t-as="doc_id">
                    <t t-raw="translate_doc(doc_id, doc_model, 'partner_id.lang', 'custom_module_name.report_object_review_document')"/>
                </t>
            </t>
        </template>
    </data>
</openerp>

custom_module_name.py

from openerp.osv import osv
from openerp import models, fields, api, _
class report_object_review(models.AbstractModel):
    _name = 'report.custom_module_name.report_object_review'
    _template = 'custom_module_name.report_object_review'
    def get_format(self):
        return 'some text!!!'
    @api.multi
    def render_html(self, data=None):
        report_obj = self.env['report']
        report = report_obj._get_report_from_name(self._template)
        docargs = {
            'get_format': self.get_format,
            'doc_ids': self._ids,
            'doc_model': report.model,
            'docs': self,
        }
        return report_obj.render(self._template, docargs)

maybe someone can tell me what is wrong with my code?

thank in advance!