def read_hierarchy(self, fid):
        """Read hierarchy information from acclaim skeleton file stream."""

        lin = self.read_line(fid)
                    
        while lin != 'end':
            parts = lin.split()
            if lin != 'begin':
                ind = self.get_index_by_name(parts[0])
                for i in range(1, len(parts)):
                    self.vertices[ind].children.append(self.get_index_by_name(parts[i]))
            lin = self.read_line(fid)
        lin = self.read_line(fid)
        return lin
Read hierarchy information from acclaim skeleton file stream.