def METHOD_NAME(self, ethane):
    assert ethane.n_bonds == 7
    assert ethane.n_angles == 0
    assert ethane.n_dihedrals == 0
    assert ethane.n_impropers == 0
    ethane.identify_connections()
    assert ethane.n_bonds == 7
    assert ethane.n_angles == 12
    assert ethane.n_dihedrals == 9
    assert ethane.n_impropers == 8