## causes_extras.py (in causes/templatetags)
from django import template
from media_library.models import Collection, Video
from locations.models import Location
from causes.models import Cause

register = template.Library()

@register.inclusion_tag('media_library/_cause_locations.html')
def get_causes(cause):
    cause_locations = Location.objects.filter(collection__causes=cause).filter(video__causes=cause)
    return {'cause_locations': cause_locations }

## _cause_locations.html
{% for location in cause_locations %}
	<a href="/">{{ location.name }}</a>{% if not forloop.last %}, {% endif %}
{% endfor %}