@staticmethod
def longer_transpositions_are_more_costly(pos1, pos2):
    """Longer Transpositions Are More Costly.

        Parameters
        ----------
        pos1 : int
            The position of the first transposition
        pos2 : int
            The position of the second transposition

        Returns
        -------
        float
            A cost that grows as difference in the positions increases

        .. versionadded:: 0.4.0

        """
    return abs(pos2 - pos1) / 9 + 1
