code: def send_status_response(environ, start_response, e, add_headers=None, is_head=False):
      
      status = get_http_status_string(e)
      headers = []
      if add_headers:
          headers.extend(add_headers)
      #    if 'keep-alive' in environ.get('HTTP_CONNECTION', '').lower():
      #        headers += [
      #            ('Connection', 'keep-alive'),
      #        ]
  
      if e in (HTTP_NOT_MODIFIED, HTTP_NO_CONTENT):
          # See paste.lint: these code don't have content
          start_response(
              status, [("Content-Length", "0"), ("Date", get_rfc1123_time())] + headers
          )
          return [b""]
  
      if e in (HTTP_OK, HTTP_CREATED):
          e = DAVError(e)
      assert isinstance(e, DAVError)
  
      content_type, body = e.get_response_page()
      if is_head:
          body = compat.b_empty
  
      assert compat.is_bytes(body), body  # If not, Content-Length is wrong!
      start_response(
          status,
          [
              ("Content-Type", content_type),
              ("Date", get_rfc1123_time()),
              ("Content-Length", str(len(body))),
          ]
          + headers,
      )
      return [body]
docs: Start a WSGI response for a DAVError or status code.