AutoModel.nonstd_restraints() — add restraints on ligands

nonstd_restraints(aln)
This method is called automatically by AutoModel after it generates the standard protein restraints. It adds restraints to keep non-standard residues (anything treated as a HETATM or BLK residue, such as ligands or metal ions) in a reasonable conformation. You can override this method if you need to change these restraints.

By default, four sets of restraints are built: