def column_index(self, elem: tuple[int, int]) -> int:
        """Gives the number of active grid cells before row element j, in column i.

        Parameters
        ----------
        elem
            (i,j) index, where i indexes columns and j rows

        Returns
        -------
        int
            The number of active grid cells before row element j, in column i,
            If (i,j) is not an active grid cell returns -1
        """
Gives the number of active grid cells before row element j, in column i.

        Parameters
        ----------
        elem
            (i,j) index, where i indexes columns and j rows

        Returns
        -------
        int
            The number of active grid cells before row element j, in column i,
            If (i,j) is not an active grid cell returns -1
        
darts/dataprocessing/dtw/window.py