code: def set_content_type(self):
          
          if self.object_name and not self.content_type:
              # XXX nothing is currently done with the encoding... we may
              # need to in the future
              self.content_type, encoding = mimetypes.guess_type(
                  self.object_name, strict=False)
docs: Set the content type based on the file extension used in the object
          name.