@classmethod
def parse(cls, string):
    """ Parse zeo++ .res format

        Example res string:

        HKUST-1.res    13.19937 6.74621  13.19937

        Containing the diameters of
         * the largest included sphere
         * the largest free sphere
         * the largest included sphere along free sphere path

        parameters
        ----------
        string: string
          string in res format

        return
        ------
        res: dict
          dictionary of output values
        """
    res = {}
    values = string.split()
    if len(values) != 4:
        raise ValueError('Found more than 4 fields in .res format')
    for i in (0, 1, 2):
        keyword = cls.keywords[i]
        res[keyword] = float(values[i + 1])
        res[keyword + '_unit'] = 'A'
    return res
