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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 get_timestamp(str_len=13):
 """ get timestamp string, length can only between 0 and 16 """

    if isinstance(str_len, integer_types) and 0 < str_len < 17:
        return builtin_str(time.time()).replace(".", "")[:str_len]

    raise ParamsError("timestamp length can only between 0 and 16.")