def __init__(self):
self.lengths = dict([bond_type, {}] for bond_type in bond_types)<EOL>self._load_bond_data()<EOL>self._approximate_unkown_bond_lengths()<EOL>self.max_length = max(<EOL>max(lengths.values())<EOL>for lengths<EOL>in self.lengths.values()<EOL>if len(lengths) > <NUM_LIT:0><EOL>)<EOL>
This object is created when importing this module. There is no need
to do it a second time manually.