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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 convertToDatetime(fmt="%Y-%m-%dT%H:%M:%S.%f"):
 """Helper to create a parse action for converting parsed datetime string to Python datetime.datetime Params - - fmt - format to be passed to datetime.strptime (default= ``"%Y-%m-%dT%H:%M:%S.%f"``) Example:: dt_expr = pyparsing_common.iso8601_datetime.copy() dt_expr.setParseAction(pyparsing_common.convertToDatetime()) print(dt_expr.parseString("1999-12-31T23:59:59.999")) prints:: [datetime.datetime(1999, 12, 31, 23, 59, 59, 999000)] """

        def cvt_fn(s,l,t):
            try:
                return datetime.strptime(t[0], fmt)
            except ValueError as ve:
                raise ParseException(s, l, str(ve))
        return cvt_fn