code: def set_level(self, level):
          
          if not level:
              return None
          self.levelmap = set()
          for char in level:
              self.levelmap = self.levelmap.union(self.levels[char])
          self.loglevel = level
          return self.loglevel
docs: Sets :attr:loglevel to @level
  
              @level: #str one or several :attr:levels