'Get the tuple of headers that will be used
for generating reply headers'

def get_reply_headers(self):

    header_tuples = self.__reply_header_list[:]
    header_names = [n for (n, v) in header_tuples]
    for (n, v) in self.reply_headers.items():
        if (n not in header_names):
            header_tuples.append((n, v))
            header_names.append(n)
    return header_tuples
