title: How to get value of variable call.data when use two IF statement
body: <p>i have a problem hope someone can help me.</p>
  <p>Ex:</p>
  <pre><code>@bot.callback_query_handler(func = lambda call: True)
      def xu_ly(call):
         if call.data == 'a':
           markup = sub_main_1_2()
           if call.data == 'a_1':
             markup = sub_main_1_2_1()
  </code></pre>
  <p>i can't get value of call.data from button have callback_data = 'a_1'</p>
  <p>Ple help me.</p>