def init_structure(self, total_num_bonds, total_num_atoms,<EOL>total_num_groups, total_num_chains, total_num_models,<EOL>structure_id):
raise NotImplementedError<EOL>
Initialise the structure object.
        :param total_num_bonds: the number of bonds in the structure
        :param total_num_atoms: the number of atoms in the structure
        :param total_num_groups: the number of groups in the structure
        :param total_num_chains: the number of chains in the structure
        :param total_num_models: the number of models in the structure
        :param structure_id the: id of the structure (e.g. PDB id)