Ok here is the code of my view.
def customers_to_be_called(request):
    customers = Customer.objects.filter(call=True)
    list_of_customers = []
    for cust in customers:
        jobs = Job.objects.filter(customer = cust)
        customer_date = {}
        customer_data['customer'] = cust
        customer_date['jobs'] = jobs
        list_of_customers.append(customer_data)
    return render(request, 'repairs/customers_to_be_called.html',
           {'list_of_customers' : list_of_customers,
    })
and here is the template that is gonna be rendered
<div>
{% for customer in list_of_customers %}
    <h2> {{customer['customer'].name}} </h2>
    <ul>
    {% for job in customer['jobs'] %}
        <li> {{job.product}} </li>
    {% endfor %}
    </ul>
{% endfor %}
</div>
But When I send a request to this page I get the following error.

I don't know why it isn't parsing customer in the template while there is data in it..??
 
    