Retrieve similar objects from a model

from Levenshtein import ratio
from django.contrib.contenttypes.models import ContentType


def get_similar_items(mod, field, string, similarity_ratio=0.6, limit=None):
    """ 
        Get similar items for a specific model
        Example usage:
        similar = get_similar_items(Entry, 'title', 'Espresso is good for you', 0.5, 10)
        var = Entry.objects.filter(id__in=similar)
    """
    similar_list_id = []
    v = ContentType.objects.get_for_model(mod)
    c = v.model_class()
    for i in c.objects.all():
        if ratio(string, getattr(i,field)) > similarity_ratio:
            similar_list_id.append(i.id)
    return similar_list_id[:limit]