Turn the raw bucket data into a list of tuples containing the key,
        number of documents and a flag indicating whether this value has been
        selected or not.

def get_values(self, data, filter_values):
        """
        Turn the raw bucket data into a list of tuples containing the key,
        number of documents and a flag indicating whether this value has been
        selected or not.
        """
        out = []
        for bucket in data.buckets:
            key = self.get_value(bucket)
            out.append((
                key,
                self.get_metric(bucket),
                self.is_filtered(key, filter_values)
            ))
        return out