def cov(self, other, min_periods=None):
        this, other = self.align(other, join='inner', copy=False)
        if len(this) == 0:
            return np.nan
        return nanops.nancov(this.values, other.values,
                             min_periods=min_periods)
Compute covariance with Series, excluding missing values
dataset/ETHPy150Open pydata/pandas/pandas/core/series.py/Series.cov