"XML or text declaration not at start of entity: line 2, column 0" when calling ElementTree.parse
<p><a href="https://docs.python.org/2/library/xml.etree.elementtree.html#xml.etree.ElementTree.parse" rel="noreferrer"><code>ElementTree.parse()</code></a> fails in the simple example below with the error</p>

<blockquote>
  <p>xml.etree.ElementTree.ParseError: XML or text declaration not at start of entity: line 2, column 0</p>
</blockquote>

<p>The XML looks valid and the code is simple, so what am I doing wrong?</p>

<pre><code>xmlExample = """
&lt;?xml version="1.0"?&gt;
&lt;data&gt;
    stuff
&lt;/data&gt;
"""
import io
source = io.StringIO(xmlExample)
import xml.etree.ElementTree as ET
tree = ET.parse(source)
</code></pre>