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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 groupby(self, values):
 """ Group the index labels by a given array of values. Parameters values : array Values used to determine the groups. Returns ------- groups : dict {group name -> group labels} """


        # TODO: if we are a MultiIndex, we can do better
        # that converting to tuples
        if isinstance(values, ABCMultiIndex):
            values = values.values
        values = ensure_categorical(values)
        result = values._reverse_indexer()

        # map to the label
        result = {k: self.take(v) for k, v in result.items()}

        return result