Getting error "content is not allowed in prolog" while parsing XML through groovy scripts

[Oct21]

Hi 

Am using groovy script to parse the XML. Am able get all the data nodes but not able to fetch the particular which i want.

Code 

assert context.response

def getData = { data, element ->
new XmlSlurper().parseText(data).'**'.find {it.name() == element}
}

def inXmlStr = getData(context.response, 'Acknowledge').text()
log.info inXmlStr
def receiptId = getData(inXmlStr, 'ReceiptId')
log.info receiptId
context.testCase.setPropertyValue('ID', receiptId.IdValue.toString())

Response XML : <?xml version="1.0" encoding="utf-8"?>
<AcknowledgeCandidateRegistration majorVersionId="1" minorVersionId="0" xmlns="http://cebtalentcentral.com">
<ApplicationArea>
<CreationDateTime>2019-02-12T15:11:05.027Z</CreationDateTime>
</ApplicationArea>
<Acknowledge>
<OriginalApplicationArea>
<CreationDateTime>2019-02-12T15:11:03.470Z</CreationDateTime>
</OriginalApplicationArea>
<ReceiptId>155785</ReceiptId> // this particular id
<Status>Completed</Status>
<RejectCode>0</RejectCode>
<RejectReason />
</Acknowledge>
<DataArea>
<AssessmentOrder>
<Assessment packageTag="A_VAT_Induct" name="Verify - Inductive Reasoning (2007)" orderItemRef="2166874" language="MULTI" stage="1" jobLevel="Graduate/University" originalTimer="00:25:00" adjustedTimer="00:25:00" />
<Report packageTag="A_VAT_Induct" name="Verify - Inductive Reasoning (2007)" orderItemRef="1698389" language="en-US" comparisonGroup="" reportFormat="Pdf" reportMedia="Link" />
<AssessmentAccess hasAssessments="true">
<Assessment stage="1">
<AssessmentCommunication>
<URI>https://integration-talentcentral-qa2.eu.shl.com/integration/ce/7d67354c372440d988d8c85dd355c48a/?ri...>
</AssessmentCommunication>
</Assessment>
</AssessmentAccess>
</AssessmentOrder>
</DataArea>
</AcknowledgeCandidateRegistration>

Regards,

Oct21