code: def get_noconflict_metaclass(bases, left_metas, right_metas):
      
      # make tuple of needed metaclasses in specified priority order
      metas = left_metas + tuple(map(type, bases)) + right_metas
      needed_metas = remove_redundant(metas)
  
      # return existing confict-solving meta, if any
      if needed_metas in memoized_metaclasses_map:
          return memoized_metaclasses_map[needed_metas]
      # nope: compute, memoize and return needed conflict-solving meta
      elif not needed_metas:         # wee, a trivial case, happy us
          meta = type
      elif len(needed_metas) == 1:  # another trivial case
          meta = needed_metas[0]
      # check for recursion, can happen i.e. for Zope ExtensionClasses
      elif needed_metas == bases:
          raise TypeError("Incompatible root metatypes", needed_metas)
      else:  # gotta work ...
          metaname = '_' + ''.join([m.__name__ for m in needed_metas])
          meta = classmaker()(metaname, needed_metas, {})
      memoized_metaclasses_map[needed_metas] = meta
      return meta
docs: Not intended to be used outside of this module, unless you know what you are doing.