docs: def process_upload(self, set_content_type=True):
          """Process the uploaded file."""
          metadata = self.get_upload_key_metadata()
  
          if set_content_type:
              content_type = self.get_upload_content_type()
              metadata.update({b'Content-Type': b'{0}'.format(content_type)})
  
          upload_key = self.get_upload_key()
          processed_key_name = self.get_processed_key_name()
          processed_key = upload_key.copy(upload_key.bucket.name,
                                          processed_key_name, metadata)
          processed_key.set_acl(self.get_processed_acl())
          upload_key.delete()
          return processed_key