def __str__(self):
        accum = ''
        for pos in self:
            for relset in self[pos]:
                i = 1
                for gf in self[pos][relset]:
                    if i==1:
                        accum += str(pos) + ': '
                    else:
                        accum += ' '*(len(str(pos))+2)
                    accum += str(gf)
                    if relset and i==len(self[pos][relset]):
                        accum += ' : ' + str(relset)
                    accum += '\n'
                    i += 1
        return accum