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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 check_time_param(t):
 """Check whether a string sent in matches the ISO8601 format. If a Datetime object is passed instead, it will be converted into an ISO8601 compliant string. :param t: the datetime to check :type t: string or Datetime :rtype: string"""


    if type(t) is str:
        if not ISO.match(t):
            raise ValueError('Date string "%s" does not match ISO8601 format' %
                             (t))
        return t
    else:
        return t.isoformat()