title: Append a tuple to a list - what's the difference between two ways?
body: <p>I wrote my first "Hello World" 4 months ago. Since then, I have been following a Coursera Python course provided by Rice University. I recently worked on a mini-project involving tuples and lists. There is something strange about adding a tuple into a list for me:</p>
  
  <pre><code>a_list = []
  a_list.append((1, 2))       # Succeed! Tuple (1, 2) is appended to a_list
  a_list.append(tuple(3, 4))  # Error message: ValueError: expecting Array or iterable
  </code></pre>
  
  <p>It's quite confusing for me. Why specifying the tuple to be appended by using "tuple(...)" instead of simple "(...)" will cause a <code>ValueError</code>?</p>
  
  <p>BTW: I used <code>CodeSkulptor</code> <a href="http://www.codeskulptor.org/" rel="noreferrer">coding tool used in the course</a></p>