title: GUIzero: "'int' object is not subscriptable" with variables that are forced to be strings
body: <p>I am working on a piece of GUIzero code intended to attach the values of a 2D array to a selection of textbox widgets. However, despite the fact that all variables in the widget value equations are forced to be strings, it still is telling me that a value is an integer.</p>
  <pre><code>    leaderboard_array = [&quot;***&quot;, 0]*5
      leaderboard_box1 = Text(leaderboard_window)
      leaderboard_box1.value = str(str(leaderboard_array[0][0]) + &quot;: &quot; + str(leaderboard_array[0][1]))
      leaderboard_box2 = Text(leaderboard_window)
      leaderboard_box2.value = str(str(leaderboard_array[1][0]) + &quot;: &quot; + str(leaderboard_array[1][1]))
      leaderboard_box3 = Text(leaderboard_window)
      leaderboard_box3.value = str(str(leaderboard_array[2][0]) + &quot;: &quot; + str(leaderboard_array[2][1]))
      leaderboard_box4 = Text(leaderboard_window)
      leaderboard_box4.value = str(str(leaderboard_array[3][0]) + &quot;: &quot; + str(leaderboard_array[3][1]))
      leaderboard_box5 = Text(leaderboard_window)
      leaderboard_box5.value = str(str(leaderboard_array[4][0]) + &quot;: &quot; + str(leaderboard_array[4][1]))
  </code></pre>
  <p>The exact error code is this:
  leaderboard_box2.value = str(str(leaderboard_array[1][0]) + &quot;: &quot; + str(leaderboard_array[1][1]))
  TypeError: 'int' object is not subscriptable</p>