hi all , iam having a custom report and when printing its showing the below error

in py :

from openerp.tools import amount_to_text

from openerp.tools import amount_to_text_en

    def amount_to_text(self, amount, currency='Dirham'):

        return amount_to_text(amount, 'en','Dirham')

    def amount_to_text_dollar(self, amount, currency='Dollar'):

        return amount_to_text_en.amount_to_text_dollar(amount,'Dollar')

in report:

<td colspan="6" style="font-family:Arial;font-size:15px;padding:2mm;text-align:left;width:100%;" width="100%"><strong>Total Amount in Words:</strong>&amp;nbsp;&amp;nbsp;<span t-esc="o.amount_to_text_dollar(o.amount_total,'Dollar')" /></td>

ERROR :

    return amount_to_text_en.amount_to_text_dollar(amount,'Dollar')
QWebException: "'module' object has no attribute 'amount_to_text_dollar'" while evaluating
"o.amount_to_text_dollar(o.amount_total,'Dollar')"


someone help me with this , version is odoo 8