code: def _cookie_attrs(self, cookies):
          
          # add cookies in order of most specific (ie. longest) path first
          cookies.sort(key=lambda a: len(a.path), reverse=True)
  
          version_set = False
  
          attrs = []
          for cookie in cookies:
              # set version of Cookie header
              # XXX
              # What should it be if multiple matching Set-Cookie headers have
              #  different versions themselves?
              # Answer: there is no answer; was supposed to be settled by
              #  RFC 2965 errata, but that may never appear...
              version = cookie.version
              if not version_set:
                  version_set = True
                  if version > 0:
                      attrs.append("$Version=%s" % version)
  
              # quote cookie value if necessary
              # (not for Netscape protocol, which already has any quotes
              #  intact, due to the poorly-specified Netscape Cookie: syntax)
              if ((cookie.value is not None) and
                  self.non_word_re.search(cookie.value) and version > 0):
                  value = self.quote_re.sub(r"\\\1", cookie.value)
              else:
                  value = cookie.value
  
              # add cookie-attributes to be returned in Cookie header
              if cookie.value is None:
                  attrs.append(cookie.name)
              else:
                  attrs.append("%s=%s" % (cookie.name, value))
              if version > 0:
                  if cookie.path_specified:
                      attrs.append('$Path="%s"' % cookie.path)
                  if cookie.domain.startswith("."):
                      domain = cookie.domain
                      if (not cookie.domain_initial_dot and
                          domain.startswith(".")):
                          domain = domain[1:]
                      attrs.append('$Domain="%s"' % domain)
                  if cookie.port is not None:
                      p = "$Port"
                      if cookie.port_specified:
                          p = p + ('="%s"' % cookie.port)
                      attrs.append(p)
  
          return attrs
docs: Return a list of cookie-attributes to be returned to server.
  
          like ['foo="bar"; $Path="/"', ...]
  
          The $Version attribute is also added when appropriate (currently only
          once per request).