title: Python Manipulate and save XML, change one property
body: <p>I have this xml:</p>
  
  <pre><code>&lt;SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
      &lt;SOAP-ENV:Body&gt;
          &lt;m:request xmlns:m="http://www.datapower.com/schemas/management" domain="XXXXX"&gt;
              &lt;m:do-action&gt;
                  &lt;FlushDocumentCache&gt;
                      &lt;XMLManager class="XMLManager"&gt;default&lt;/XMLManager&gt;
                  &lt;/FlushDocumentCache&gt;
                  &lt;FlushStylesheetCache&gt;
                      &lt;XMLManager class="XMLManager"&gt;default&lt;/XMLManager&gt;
                  &lt;/FlushStylesheetCache&gt;
              &lt;/m:do-action&gt;
          &lt;/m:request&gt;
      &lt;/SOAP-ENV:Body&gt;
  &lt;/SOAP-ENV:Envelope&gt;
  </code></pre>
  
  <p>I want to change only the value XXXXX of the domain property.</p>
  
  <p>I did something like this :</p>
  
  <pre><code>import xml.etree.ElementTree as etree
  tree = etree.parse('input.xml')
  # HOW TO FIND THE VALUE XXXXX AND CHANGE IT WITH A NEW VALUE ???
  tree.write('output.xml')
  </code></pre>
  
  <p>Thanks.</p>