def join(self, other, how='left', level=None, return_indexers=False):
        if (not isinstance(other, DatetimeIndex) and len(other) > 0 and
            other.inferred_type not in ('floating', 'mixed-integer',
                                        'mixed-integer-float', 'mixed')):
            try:
                other = DatetimeIndex(other)
            except (TypeError, ValueError):
                pass

        this, other = self._maybe_utc_convert(other)
        return Index.join(this, other, how=how, level=level,
                          return_indexers=return_indexers)
Compute the residual (= negative gradient).
dataset/ETHPy150Open pydata/pandas/pandas/tseries/index.py/DatetimeIndex.join--crossover with--dataset/ETHPy150Open scikit-learn/scikit-learn/sklearn/ensemble/gradient_boosting.py/BinomialDeviance.negative_gradient