Django: TemplateSyntaxError - Could not parse the remainder

Exception Value: Could not parse the remainder: '['image/jpeg',' from '['image/jpeg','

Why am I getting this TemplateSyntaxError for the code below?

{% for file in resource.files.all %}

        {% if file.file.content_type|lower in ['image/jpeg', 'image/png', 'image/gif'] %}
          <a class="resource-image" title="{{ file.id }}" href="{{ file.file.url }}">
            <img width="100%" src="{{ file.file.url }}" alt="{{ file.id }} Image"/>
          </a>

        {% elif file.file.content_type|lower in ['video/mp4', 'video/wmv', 'video/mkv', 'video/x-flv', 'video/webm', 'video/mpeg'] %}
          <video width="100%" controls>
            <source src="{{ file.file.url }}">
          </video>

        {% elif file.file.content_type|lower in ['audio/mp4', 'audio/m4a', 'audio/wav', 'audio/x-wav', 'audio/ogg'] %}
          <audio width="100%" controls>
            <source src="{{ file.file.url }}">
          </audio>

        {% elif file.file.content_type|lower in ['application/pdf'] %}
          <!-- <embed src="{{ file.file.url }}" width="800px" height="2100px" /> -->

        {% endif %}

        <p class="small text-muted">{{ file.id }}</p>

{% endfor %}

I've checked the entire template file, and all the brackets are balanced. I can't find any syntax errors.

You cannot create lists, or tuples, within the template system. Declare in Python and send them as iterators in render() function.

from django.shortcuts import render

def my_view(request):
    list_types = ['image/jpeg', 'image/png', 'image/gif']
    return render(request, 'index.html', {
        'list_types': list_types,
    })