from scrapy import Item, Field

 class Attributes(Item):
   url  = Field()
   keywords = Field(input_processor=Split())
   words = Field(input_processor=Split())
   medias = Field()
   links = Field()
   tags = Field()
   semantics = Field()
   injections = Field()

 class Split():
   def __call__(self, values):
     return [word for value in values for word in value.split()]