code: def run(self, files, stack):
          "Convert dates"
          for filename, post in files.items():
              if self.date_field in post.metadata:
                  post[self.date_field] = parse(post[self.date_field]f run(self, files, stack):
          "Convert dates"
          for filename, post in files.items():
              if self.date_field in post.metadata:
                  post[self.date_field] = parse(post[self.date_field])
docs: Convert dates