How to create table include rowspan tag by loop (python)

Please help me for coding to create table by use loop.

I need a table like this.

https://ibb.co/fqcFxcC

I use python and django in my project. I have problem in 'Additional Cost', I can't complete it because it must merge row by rowspan.

This is my template.html

<table border=1 >
        <thead>
            <tr>
                <th>Import ID</th>
                <th>Date</th>
                <th>Product</th>
                <th>Amount</th>
                <th>Cost</th>
                <th>Additional Cost</th>
        </thead>
        <tbody align="center">
            {% for imp in import_list %}
            <tr>
                <td rowspan={{imp.row_span}}><a href="{% url 'edit_import_history' imp.id %}">#{{imp.id}}</a></td>
                <td rowspan={{imp.row_span}}>{{imp.import_date}}</td>
                {% for imp_pd in importproduct %}
                {% if imp_pd.import_id.id == imp.id %}
                <td>
                    {{imp_pd.product_id.product_name}}</td>
                <td>{{imp_pd.import_amount}}</td>
                <td>{{imp_pd.import_price}}</td>
                {% if imp_pd.import_id.row_span > 1 %}
            <tr>
            </tr>
            {% endif %}
            {% endif %}
            {% endfor %}
            </tr>
            {% endfor %}
        </tbody>
    </table>

Ps. imp.rowspan = [count of products in each import id - (count of product in each import - 1)] It should equal count of products in each import id but I don't know which way is better.

example at Import ID #1 have 3 product (A,B,C) if should rowspan 3 but in my solution rowspan is 3+(3-1) = 5 rowspan