code: def process(self, processor:PreProcessors=None):
          "Apply `processor` or `self.processor` to `self`."
          if processor is not None: self.processor = processor
          self.processor = listify(self.processor)
          for p in self.processor: p.process(self)
          return self process(self, processor:PreProcessors=None):
          "Apply `processor` or `self.processor` to `self`."
          if processor is not None: self.processor = processor
          self.processor = listify(self.processor)
          for p in self.processor: p.process(self)
          return self
docs: Apply `processor` or `self.processor` to `self`.