code: def _update_type(self, params):
          
          dozscale = False
          particles = []
          for p in listify(params):
              typ, ind = self._p2i(p)
              particles.append(ind)
              dozscale = dozscale or typ == 'zscale'
          particles = set(particles)
          return dozscale, particles
docs: Returns dozscale and particle list of update