title: pygame mouse registering multiple clicks
body: <p>I have two lists and a function. The function appends items from one list to the other every time the mouse is clicked. However, the mouse sometimes appends more than one item from the list. After doing a little digging around I found that this was because the mouse is held down for too long. How do I make it so regardless of how long the mouse is held down, it only appends one item? Here is a code sample:</p>
  
  <pre><code>list_A = [1,2,3,4,5,6]
  list_B = []
  
  def appender():
      if mouse.get_pressed()[0] = 1
          list_B.append(list_A[len(list_A)-1])
          list_A.remove(list_A[len(list_A)-1])
  </code></pre>
  
  <p>I call the appended function inside of a game loop with all the right setups. However, it appends multiple items when the mouse is held down, any suggestions?</p>