Hi Samantha

Your error is due to this line:

'get_data': self._get_data(voucher), 

because you are getting the result of the _get_data method call and assign it to the localcontext dict. Change it to:

'get_data': self._get_data, 

And you will be ok. The localcontext is were you put some info available to the report and for function calls in the report you need to use the function object reference

I can't edit my question.

This is my code (as of now) but it returns an error: 

QWebException: ""'account.voucher.pay.detail' object is not callable" while evaluating
'get_data(o)'" while evaluating

report_parser.py

from openerp import models
from openerp.report import report_sxw

class report_parser(report_sxw.rml_parse):
    def __init__(self, cr, uid, name, context):
        super(pdc_report_parser, self).__init__(cr, uid, name, context=context)
        active_ids = context.get('active_ids')
        account_voucher = self.pool.get('account.voucher')
        docs = account_voucher.browse(cr, uid, active_ids, context)

        voucher = []
        for voucher_id in active_ids:
            voucher_id = account_voucher.browse(cr, uid, voucher_id, context)
            voucher.append(voucher_id)

        self.localcontext.update({
            'docs': docs,     
            'get_data': self._get_data(voucher),      
            'hello_world': self._hello,
        })

    def _hello(self):
        return "Hello World!"

    #It returns all ids of the object 'account.voucher.pay.detail' based on voucher_ids that was selected
    def _get_data(self, voucher_id):
        print "voucher_id:", voucher_id
        pay_details = []
        account_voucher_pay_detail = self.pool['account.voucher.pay.detail']

        for rec in voucher_id:

            details = account_voucher_pay_detail.search(self.cr, self.uid,
                    [('voucher_id', '=', rec.id)])
            if details:
                pay_details = pay_details + details
 
        pay_details = account_voucher_pay_detail.browse(self.cr, self.uid, pay_details)
        return pay_details

class pdc_report_parser_test(models.AbstractModel):
    _name = 'report.parser_module.report_test_document'
    _inherit = 'report.abstract_report'
    _template = 'parser_module.report_test_document'
    _wrapped_report_class = report_parser

report_test_document.xml

<?xml version="1.0" encoding="utf-8"?>
<!--Custom report.-->
<openerp>
<data>
<template id="report_test_doc">
    <t t-call="module_parser.my_layout">
        <div class="page">
            <table class="table table-condensed">
                <thead>
                    <tr>
                        <th>Transaction Date</th>
                        <th>Check Date</th>
                        <th>Bank/Branch</th>
                        <th>Check No.</th>
                        <th>Amount</th>
                        <t t-if="o.partner_id.customer">
                        	<th>Customer</th>
                        </t>
                        <t t-if="o.partner_id.supplier">
                        	<th>Supplier</th>
                        </t>
                    </tr>
                </thead>
 
                <tr t-foreach="get_data(o)" t-as="pd">
                  <td>
                      <span t-field="o.date"/>
                  </td>
                  <td>
                      <span t-field="pd.date_due"/>
                  </td>
                  <td>
                      <span t-field="pd.name"/>
                  </td>
                  <td>
                      <span t-field="pd.check_no"/>
                  </td>
                  <td>
                      <span t-field="pd.amount"/>
                  </td>
                  <td>
                      <span t-field="o.partner_id.name"/>
                  </td>
                </tr>
        	</table>
        </div>
    </t>
</template>
<template id="report_test_document">
    <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', 'module_parser.report_test_doc')"/>
        </t>
    </t>
</template>
</data>
</openerp>

In the default, it can print all necessary information but per page (1 voucher, 1 page) not in one page only (all vouchers selected in one page)