[Python] How to insert a processing instruction in XML file?

I want to add a xml-stylesheet processing instruction before the root element in my XML file using ElementTree (Python 3.8).

You find as below my code that I used to create XML file

import xml.etree.cElementTree as ET

def Export_star_xml( self ):
star_element = ET.Element("STAR",**{ 'xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance' })
element_node = ET.SubElement(star_element ,"STAR_1")
element_node.text = "Mario adam"
tree.write( "star.xml" ,encoding="utf-8", xml_declaration=True )


Output:

<?xml version="1.0" encoding="windows-1252"?>
<STAR xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<STAR_1> Mario adam </STAR_1>
</STAR>


Output Expected:

<?xml version="1.0" encoding="windows-1252"?>
<?xml-stylesheet type="text/xsl" href="ResourceFiles/form_star.xsl"?>
<STAR xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<STAR_1> Mario adam </STAR_1>
</STAR>

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