docs: def get_headers(data, extra_headers=None):
      '''
      Takes the response data as well as any additional headers and returns a
      tuple of tuples of headers suitable for passing to start_response()
      '''
      response_headers = {
          'Content-Length': str(len(data)),
      }
  
      if extra_headers:
          response_headers.update(extra_headers)
  
      return list(response_headers.items())