code: func focusedAndNotIgnored(locs []*Location, m map[uint64]bool) bool {
  	var f bool
  	for _, loc := range locs {
  		if focus, focusOrIgnore := m[loc.ID]; focusOrIgnore {
  			if focus {
  				// Found focused location. Must keep searching in case there
  				// is an ignored one as well.
  				f = true
  			} else {
  				// Found ignored location. Can return false right away.
  				return false
  			}
  		}
  	}
  	return f
  }
docs: // focusedAndNotIgnored looks up a slice of ids against a map of
  // focused/ignored locations. The map only contains locations that are
  // explicitly focused or ignored. Returns whether there is at least
  // one focused location but no ignored locations.