ElementTree TypeError "write() argument must be str, not bytes" in Python3 : <p>Got a Problem with generating a .SVG File with Python3 and ElementTree.</p>

<pre><code>    from xml.etree import ElementTree as et
    doc = et.Element('svg', width='480', height='360', version='1.1', xmlns='http://www.w3.org/2000/svg')

    #Doing things with et and doc

    f = open('sample.svg', 'w')
    f.write('&lt;?xml version=\"1.0\" standalone=\"no\"?&gt;\n')
    f.write('&lt;!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\"\n')
    f.write('\"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\"&gt;\n')
    f.write(et.tostring(doc))
    f.close()
</code></pre>

<p>The Function et.tostring(doc) generates the TypeError "write() argument must be str, not bytes". I don't understand that behavior, "et" should convert the ElementTree-Element into a string? It works in python2, but not in python3. What did i do wrong?</p>
