I apologize in advance if this is off topic. I heard that people use chimerax mailing list to share tips and ask for help and saw some archives online that came in handy.

I'm wondering if it's possible to set an attribute on the whole atomic chain (for future byattribute coloring) the way it is done in the example with Atom/Residue ? (https://rbvi.github.io/chimerax-recipes/helixmlp/helixmlp.html)

I'm trying something similar in my script:
```
from chimerax.core.commands import run
from chimerax.atomic import Residue, Atom, Chain

# the regular Cmd setup..

c:Chain
polyclass:str = ... input from external spruce
c.polymer_class = polyclass
Chain.register_attr(session, 'polymer_class', 'Polymer Class', attr_type = str)
```

But when i run `color byattribute polymer_class /6 palette lipophilicity` it's not getting picked up:
`No known/registered numeric attribute polymer_class`.
Maybe it's not possible to color by string attributes?

Thanks a lot for your advice

Artem