title: How does unicodedata.normalize(form, unistr) work?
body: <p>On the API doc, <a href="http://docs.python.org/2/library/unicodedata.html#unicodedata.normalize" rel="noreferrer">http://docs.python.org/2/library/unicodedata.html#unicodedata.normalize</a>. It says </p>
  
  <blockquote>
    <p>Return the normal form <em>form</em> for the Unicode string <em>unistr</em>. Valid values for form are ‘NFC’, ‘NFKC’, ‘NFD’, and ‘NFKD’.` </p>
  </blockquote>
  
  <p>The documentation is rather vague, can someone explain the <code>valid values</code> with some examples?</p>