title: _pickle.UnpicklingError: invalid load key, '['
body: <p>I'm currently programming a simple pygame platformer, and I'm using Python's <code>pickle</code> module. For each of the levels I have different files. I'm trying to store them in the <code>world_data</code> variable with this code:</p>
  <pre><code>if path.exists(f'level{level}_data'):
      pickle_in = open(f'level{level}_data', 'rb')
      world_data = pickle.load(pickle_in)
  world = World(world_data)
  </code></pre>
  <p>but it gives me this error:</p>
  <pre><code>line 333, in &lt;module&gt;
      world_data = pickle.load(pickle_in)
  _pickle.UnpicklingError: invalid load key, '['.
  </code></pre>
  <p>I searched everywhere but couldn't find an answer.</p>
  <p>This is what one of my level files look like:</p>
  <pre><code>[
  [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
  [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
  [1, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 1],
  [1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 2, 2, 1],
  [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 0, 7, 0, 5, 0, 0, 0, 1],
  [1, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 2, 2, 0, 0, 0, 0, 0, 1],
  [1, 7, 0, 0, 2, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
  [1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
  [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 7, 0, 0, 0, 0, 1],
  [1, 0, 2, 0, 0, 7, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
  [1, 0, 0, 2, 0, 0, 4, 0, 0, 0, 3, 0, 0, 3, 0, 0, 0, 0, 0, 1],
  [1, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 0, 0, 0, 1],
  [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
  [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 7, 0, 0, 0, 0, 2, 0, 1],
  [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
  [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 2, 2, 2, 2, 2, 1],
  [1, 0, 0, 0, 0, 0, 2, 2, 2, 6, 6, 6, 6, 6, 1, 1, 1, 1, 1, 1],
  [1, 0, 0, 0, 0, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
  [1, 0, 0, 0, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
  [1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
  ]
  </code></pre>
  <p>Do I got something wrong with my file? Or something wrong with my code? Please help me</p>