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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 solar_zenith(self, dateandtime, latitude, longitude):
 """Calculates the solar zenith angle. :param dateandtime: The date and time for which to calculate the angle. :type dateandtime: :class:`~datetime.datetime` :param latitude: Latitude - Northern latitudes should be positive :type latitude: float :param longitude: Longitude - Eastern longitudes should be positive :type longitude: float :return: The zenith angle in degrees from vertical. :rtype: float If `dateandtime` is a naive Python datetime then it is assumed to be in the UTC timezone. """


        return 90.0 - self.solar_elevation(dateandtime, latitude, longitude)