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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 trend_coefficients(self, order=LINEAR):
        '''Calculate trend coefficients for the specified order.'''
        if not len(self.points):
            raise ArithmeticError('Cannot calculate the trend of an empty series')
        return LazyImport.numpy().polyfit(self.timestamps, self.values, order)