django admin edit form not getting file value

Question

In my html i have a code like :

<div class="col-md-4 form-group">
    <label for="file1">License<span class="req">*</span></label><br>
    {% if data.data.licence %}
    <p class="file-upload">Currently: <a
            href="/media/{{data.data.licence}}">{{data.data.licence}}</a>
        <br>
        Change:
        <input type="file" name="licence" accept="image/*" id="licence">
    </p>
    {%else%}
    <input type="file" required name="licence" id="licence">
    {%endif%}
</div>

and in my code i am getting value like :

document = request.FILES['licence']

but i am not getting the value in edit form cae whem i am doing this can anyone please help me related this ?? i dont know what i am doing wrong here in my code my add code is working fine where i am getting value from the form and saving data in db like :

vendor/licence/ticket.png