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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 get_index(self, label):
 """ Find the index of the input ``label``. Parameters labels : int The label numbers to find. Returns ------- index : int The array index. Raises ------ ValueError If ``label`` is invalid. """


        self.check_labels(label)
        return np.searchsorted(self.labels, label)