Return the average diamension of a molecule.

        Returns
        -------
        :class:`float`
            The average dimension of the molecule.

def calculate_average_diameter(self, **kwargs):
        """
        Return the average diamension of a molecule.

        Returns
        -------
        :class:`float`
            The average dimension of the molecule.

        """
        self.average_diameter = find_average_diameter(
            self.elements, self.coordinates, **kwargs)
        return self.average_diameter