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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 centred_timegrid(cls, simulationstep):
 """Return a |Timegrid| object defining the central time points of the year 2000 for the given simulation step. Timegrid('2000-01-01 12:00:00', '2001-01-01 12:00:00', '1d') """

        simulationstep = Period(simulationstep)
        return Timegrid(
            cls._STARTDATE+simulationstep/2,
            cls._ENDDATE+simulationstep/2,
            simulationstep)