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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 datetimes(self):
 """Datetimes in wea file."""

        if self.timestep == 1:
            return tuple(dt.add_minute(30) for dt in
                         self.direct_normal_irradiance.datetimes)
        else:
            return self.direct_normal_irradiance.datetimes