Python program isn't displaying an output
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/9672615/how-can-i-determine-if-user-input-is-a-valid-hexadecimal-number">How can I determine if user input is a valid hexadecimal number? </a><br>
  <a href="http://stackoverflow.com/questions/9675229/python-program-not-displaying-as-intended">Python - Program not displaying as intended</a>  </p>
</blockquote>



<pre><code>#Hex Check
def Check(HexInput):
    while True:
        if HexInput in Valid:
            print('That is a valid hex number.')
        else:
            print('That is an invalid hex number.')
        return HexInput       

HexInput=input('Enter a hex number: ')
Valid='1234567890ABCDEFG'
</code></pre>

<p>Program needs to contain Check(). It should ask the user to input a hex number and tell them whether it's a valid hex number or not.</p>
