title: How the 4 more bytes for each characters are utilized
body: <p>I experiment on the array</p>
  
  <pre><code>In [38]: arr = []                                                                                                                                     
  
  In [39]: for k in range(10): 
      ...:     arr.append("s") 
      ...:     print(f"Length: {k:2d}, size: {sys.getsizeof(arr): 3d}") 
      ...:                                                                                                                                              
  Length:  0, size:  96
  Length:  1, size:  96
  Length:  2, size:  96
  Length:  3, size:  96
  Length:  4, size:  128
  Length:  5, size:  128
  Length:  6, size:  128
  Length:  7, size:  128
  Length:  8, size:  192
  Length:  9, size:  192
  </code></pre>
  
  <p>it could be concluded that, each character takes (128-96)/ 4 = 8 bytes.</p>
  
  <p>As I know, python utilize unicode which take 4 bytes for each character.</p>
  
  <p>Python's character has 4 more bytes.</p>
  
  <p>Could you please provide any hints how the 4 more bytes are utilized?</p>