Is there a general principle for how we treat a י"א = יש אומרים (*yesh omrim*, "some say") cited in the Shulchan Aruch (or Rama) for the purposes of determining halacha? If not, are there examples of two halachos where we use different approaches towards a י"א (e.g. following one but not the other, treating one as going *l'chumra* and one as going *l'kula*, etc.)?