#NEWLINE# def cov( self , other , min_periods = None ) : #NEWLINE# #INDENT# '\n        Compute covariance with Series, excluding missing values\n\n        Parameters\n        ----------\n        other : Series\n        min_periods : int, optional\n            Minimum number of observations needed to have a valid result\n\n        Returns\n        -------\n        covariance : float\n\n        Normalized by N-1 (unbiased estimator).\n        ' #NEWLINE# ( this , other ) = self . align ( other , join = 'inner' , copy = False ) #NEWLINE# if ( len ( this ) == 0 ) : #NEWLINE# #INDENT# return np . nan #NEWLINE# #UNINDENT# return nanops . nancov ( this . values , other . values , min_periods = min_periods )