How fix error error de xml XmlPullParserExceptionen Python, Django

Using the Python requests library I need to make a query through an XML to GeoServer which I need to return a GeoTIFF format image. This is the query:

   def ParqueNacional(request):
      context={}
      if request.method=='POST' :
    nombre="areaProtegidaParqueNacional"
    cantidad=request.POST['cantidad']
    prioridad=request.POST['prioridad']
    inclusion=request.POST['inclusion']
    operador=request.POST['operador']

    payload="""
    <?xml version="1.0" encoding="UTF-8"?><wps:Execute version="1.0.0" service="WPS" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.opengis.net/wps/1.0.0" xmlns:wfs="http://www.opengis.net/wfs" xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1" xmlns:gml="http://www.opengis.net/gml" xmlns:ogc="http://www.opengis.net/ogc" xmlns:wcs="http://www.opengis.net/wcs/1.1.1" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0 http://schemas.opengis.net/wps/1.0.0/wpsAll.xsd">
  <ows:Identifier>ras:Jiffle</ows:Identifier>
  <wps:DataInputs>
    <wps:Input>
      <ows:Identifier>coverage</ows:Identifier>
      <wps:Reference mimeType="image/geotiff" xlink:href="http://geoserver/wcs" method="POST">
        <wps:Body>
          <wcs:GetCoverage service="WCS" version="1.1.1">
            <ows:Identifier>pad:"""+ nombre +"""</ows:Identifier>
            <wcs:DomainSubset>
              <ows:BoundingBox crs="http://www.opengis.net/gml/srs/epsg.xml#32719">
                <ows:LowerCorner>225000 6800000</ows:LowerCorner>
                <ows:UpperCorner>590000 7100000</ows:UpperCorner>
              </ows:BoundingBox>
            </wcs:DomainSubset>
            <wcs:Output format="image/geotiff"/>
          </wcs:GetCoverage>
        </wps:Body>
      </wps:Reference>
    </wps:Input>
    <wps:Input>
      <ows:Identifier>script</ows:Identifier>
      <wps:Data>
        <wps:LiteralData> dem=src[0]; dem2=dem""" + operador + str(cantidad) +""" ? 1:0;  dest= (dem2); </wps:LiteralData>
      </wps:Data>
    </wps:Input>
    <wps:Input>
      <ows:Identifier>outputType</ows:Identifier>
      <wps:Data>
        <wps:LiteralData>INTEGER</wps:LiteralData>
      </wps:Data>
    </wps:Input>
  </wps:DataInputs>
  <wps:ResponseForm>
    <wps:RawDataOutput mimeType="image/geotiff">
      <ows:Identifier>result</ows:Identifier>
    </wps:RawDataOutput>
  </wps:ResponseForm>
</wps:Execute>
    """
    headers={
    "Content-type":"text/xml",
    "service":"wcs",
    "version":"1.0.0",
    "format":"image/geotiff",
    }
    url='locahost
    http = urllib3.PoolManager()
    encode=urllib.parse.quote_plus(payload)
    with open('core/static/core/img/test.geotiff','wb') as f:
      response = requests.post(url , data=payload, headers=headers, auth=("I","pass"), timeout=None, stream=True)
      for data in response.iter_content(1024):
        f.write(data)
    
    assert(response.status_code==200)
 
  return render(request,"core/ParqueNacional.html",context )

but this is the error that returns me:

<?xml version="1.0" encoding="UTF-8"?><ows:ExceptionReport xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:ows="http://www.opengis.net/ows" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.0.0" xsi:schemaLocation="http://www.opengis.net/ows localhost">
<ows:Exception exceptionCode="NoApplicableCode">
<ows:ExceptionText>org.xmlpull.v1.XmlPullParserException: processing instruction can not have PITarget with reserveld xml name (position: START_DOCUMENT seen n    &lt;?xml ... @2:11) 
processing instruction can not have PITarget with reserveld xml name (position: START_DOCUMENT seen n    &lt;?xml ... @2:11) </ows:ExceptionText>
</ows:Exception>
</ows:ExceptionReport>

How can I fix this error?

payload="""
<?xml version

payload="""<?xml version