def METHOD_NAME(**kwargs):
    """
    Gets the ratio/density that applies to the date provided
    """
    model_name = kwargs.pop('model_name')
    effective_date = kwargs.pop('effective_date')
    model = apps.get_model('api', model_name)
    return model.objects.filter(
        effective_date__lte=effective_date,
        **kwargs
    ).exclude(
        expiration_date__lt=effective_date
    ).exclude(
        expiration_date=F('effective_date')
    ).order_by('-effective_date', '-update_timestamp').first()