how to access a parent model

[Krzysztof Drozd]

i have a problem

lets sey i have a Poll model like this in tutorial. how to get access
to question field in Poll model form the Choice class (model)? i von
use this in search_fields?

or/and how to get one or more fields from choice model in poll model to
use it in search field?
like this 
search_fields = ['Choice.choice','name',],

thanks