I have span tag which contain a method define in parser now I want to add additional parameter and used in inherit xml template How can I so existing methods get replaced with new, Below is my xml code for main model:

<?xml version="1.0" encoding="UTF-8" ?>

<odoo>
    <template id="report_team_wizard_multi">
        <t t-call="web.html_container">
            <t t-call="web.external_layout">
                <center>
                    <h3>Pay Slip</h3>
                </center>
                <t t-foreach="docs" t-as="emp">
                    <strong>Date:</strong>
                    <sapn t-esc="data['form']['date']"/> <!--fields used from wizard must be like this-->
                    <br/>
                    <strong class="text-uppercase">Name:</strong>
                    <span t-field="emp.name"/>
                    <br/>
                    <strong class="text-uppercase">Email:</strong>
                    <span t-field="emp.email"/>
                    <br/>
                    <strong class="text-uppercase">Department:</strong>
                    <span t-field="emp.comp_name"/>
                    <br/>
                    <strong class="text-uppercase">Contact Number:</strong>
                    <span t-field="emp.phone"/> <!--TODO 8.8 print information from model-->
                    <br/>
                    <strong class="text-uppercase">Reporting To:</strong>
                    <span t-field="emp.parent_id"/>
                    <br/>
                    <br/>
                    <table width="100%" class="table-primary">
                        <thead>
                            <th>Month</th>
                            <th>Basic</th>
                            <th>Allowance</th>
                            <th>Deduction</th>
                        </thead>
                        <t t-foreach="emp.salary_ids" t-as="sal">
                            <tr>
                                <td>
                                    <span t-field="sal.month"/>
                                </td>
                                <td>
                                    <span t-field="sal.basic"/>
                                </td>
                                <td class="text-success">
                                    <span t-field="sal.allowance"/>
                                </td>
                                <td class="text-danger">
                                    <span t-field="sal.deduction"/>
                                </td>
                            </tr>
                        </t>
                    </table>
                    <br/>
                    <br/>
                    <td>
                        <b>Total Gross:</b>
                    </td>
                    <span t-esc="get_total_gross(emp.salary_ids)"/>
                    <br/>
                    <td>
                        <b>House Rent Allowance:</b>
                    </td>
                    <span t-esc="data['form']['house_rent_allowance']"/>  <!--TODO 8.8 wizard's field-->
                    <br/>
                    <td>
                        <b>CTC:</b>
                    </td>
                    <span t-esc="get_ctc(emp.salary_ids, data['form']['house_rent_allowance'])"/>
                    <br/>
                    <br/>
                    <br/>
                    <br/>
                    <b>
                        <h3>
                            <span t-esc="sign"/>
                        </h3>
                    </b>
                    <br/>
                    <br/>
                    <center>
                        <h8>
                            <b>NOTE:</b>
                            Benefit for all employee will be 10000, Total Gross + Benefits + House Rent Allowance = CTC
                        </h8>
                    </center>
                </t>
            </t>
        </t>
    </template>
</odoo>

And Here my inherit xml:

<?xml version="1.0" encoding="UTF-8" ?>

<!-- TODO: 8.18 -->
<odoo>
    <template id="report_team_wizard_multi_inherit" inherit_id="workshop_aftersales.report_team_wizard_multi">
        <xpath expr="//span[@t-field='emp.parent_id']" position="after">
            <br/>
            <br/>
            <strong>Medical Insurance:</strong>
            <span t-esc="data['form']['med_insure']"/>
        </xpath>

        <xpath expr="//span[@t-esc='get_ctc(emp.salary_ids, data['form']['house_rent_allowance'])']" position="replace">
<!--        <xpath expr="//a[@name='ctc']" position="before">-->
            <span t-esc="get_ctc(emp.salary_ids, data['form']['house_rent_allowance'], data['form']['med_insure'])"/>
        </xpath>
    </template>
</odoo>

This gave me error, lxml.etree.XPathSyntaxError: Invalid predicate

Thank you.