[chimera-dev] Iterating through chains

Hello, I'm trying to create a chimera script and am stumped. I'm trying to iterate through a series of PDB entries that contain a specific protein-protein interaction (some are NMR ensembles) to create a list of residues that within specific distances of the binding interface. I am able to successfully iterate through pdb files and residues, but am having difficulty iterating through chains of NMR ensembles. Is there a variable like m.chains or is the number of chains accessible through chimera.openModels.list? Also, do you have any example scripts that could help me? Sincerely, Ryan Doherty