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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def import_json():
    '''
    Import a json module, starting with the quick ones and going down the list)
    '''
    for fast_json in ('ujson', 'yajl', 'json'):
        try:
            mod = __import__(fast_json)
            log.trace('loaded %s json lib', fast_json)
            return mod
        except ImportError:
            continue