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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 aggregate_stat(origin_stat, new_stat):
 """ aggregate new_stat to origin_stat. Args: origin_stat (dict):
 origin stat dict, will be updated with new_stat dict. new_stat (dict):
 new stat dict. """

    for key in new_stat:
        if key not in origin_stat:
            origin_stat[key] = new_stat[key]
        elif key == "start_at":
            # start datetime
            origin_stat[key] = min(origin_stat[key], new_stat[key])
        else:
            origin_stat[key] += new_stat[key]