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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 append(self, other):
 """Appends stars from another StarPopulations, in place. :param other: Another :class:`StarPopulation`; must have same columns as ``self``. """

        if not isinstance(other,StarPopulation):
            raise TypeError('Only StarPopulation objects can be appended to a StarPopulation.')
        if not np.all(self.stars.columns == other.stars.columns):
            raise ValueError('Two populations must have same columns to combine them.')

        if len(self.constraints) > 0:
            logging.warning('All constraints are cleared when appending another population.')

        self.stars = pd.concat((self.stars, other.stars))

        if self.orbpop is not None and other.orbpop is not None:
            self.orbpop = self.orbpop + other.orbpop