python unique function

uniq.py

def uniq(array, callback=None):
    seen = []
    result = []
    for obj in array:
        if callback:
            key = callback(obj)
        else:
            key = obj
        if key not in seen:
            seen.append(key)
            result.append(obj)
    return result

>>> uniq([{'id':1},{'id':2},{'id':2}], lambda x: x['id'])
[{'id':1},{'id':2}]
>>> uniq([1,2,2,3])
[1,2,3]