title: sys.getsizeof() results don't quite correlate to structure size
body: <p>I am trying to create a list of size 1 MB. while the following code works:</p>
  
  <pre><code>dummy = ['a' for i in xrange(0, 1024)]
  sys.getsizeof(dummy)
  Out[1]: 9032
  </code></pre>
  
  <p>The following code does not work.</p>
  
  <pre><code>import os
  import sys
  
  dummy = []
  dummy.append((os.urandom(1024))
  sys.getsizeof(dummy)
  Out[1]: 104
  </code></pre>
  
  <p>Can someone explain why?</p>
  
  <p>If you're wondering why I am not using the first code snippet, I am writing a program to benchmark my memory by writing a for loop that writes blocks (of size 1 B, 1 KB and 1 MB) into memory. </p>
  
  <pre><code>start = time.time() 
  for i in xrange(1, (1024 * 10)):  
       dummy.append(os.urandom(1024)) #loop to write 1 MB blocks into memory
  end = time.time()
  </code></pre>