This makes restraints enforcing an -helix (mainchain conformation class ``A'') for the residue segment specified by residues (which can be created using the model.residue_range() function). The helix is restrained by binormal restraints, N-O hydrogen bonds, - distances for , -O distances for , and O-O distances for 6.1. Note that this requires all heavy atoms to be present to work properly, so will not work with the -only topology.
To actually add the restraints, pass the new object to restraints.add(). See Section 2.2.9 for an example.