code: def flex_loader(alias):
      
      if not alias.startswith('flex.'):
          return
  
      try:
          if alias.startswith('flex.messaging.messages'):
              import pyamf.flex.messaging
          elif alias.startswith('flex.messaging.io'):
              import pyamf.flex
          elif alias.startswith('flex.data.messages'):
              import pyamf.flex.data
  
          return CLASS_CACHE[alias]
      except KeyError:
          raise UnknownClassAlias(alias)
docs: Loader for L{Flex<pyamf.flex>} framework compatibility classes.
  
      @raise UnknownClassAlias: Trying to load an unknown Flex compatibility class.