code: def max_quality(self):
      return (
          max(
              m.max_quality()
              for m in self._submatchers
              if m.is_active()
          )
          * self._boost
      )
  
imports: from __future__ import division
  from array import array
  from whoosh.compat import xrange
  from whoosh.matching import mcore
label_desc: Use image node_id 3 for calling the CombinationMatcher obj's underlying member method code with example usage: obj.max_quality() and returns: unknown