title: How to fix 'TypeError: move_to_right() missing 1 required positional argument: 'learner''
body: <p>I am new to Python so forgive me if this is a rookie mistake. My objective is to have two list boxes and when I double click an item in the list on the left, it removes it then adds it to the list on the right, and vise versa. The issue I am currently having is that I am 'missing 1 required positional argument:'learner''.</p>
  
  <p>I don't quite understand why I am receiving this error as I believe I am already giving the parameter 'learner'. As shown in my code 'learner' is used within the brackets of my function.</p>
  
  <pre><code>def move_to_right(self, learner):  
      self.buttonHandler(learner)  
  
  for learner in concatstring:  
      filteredlistbox.insert("end", learner)  
      filteredlistbox.bind('&lt;Double-Button-1&gt;', lambda: self.move_to_right(learner))  
  move_to_right(learner) 
  </code></pre>
  
  <p>I would expect this to run smoothly, as in my eyes I am giving it the required parameter. But it's likely I am missing something that I do not realise.</p>