Function saying i cannot redeclare php - php

Question

I am working with an API that has a function called invokeGetMatchingProductForId() and every time the script is run, this error occurs. I am attempting to loop through the script to change one variable but i am not sure if that is the problem. If you guys have any suggestions let me know. Any help would be much appreciated! Thanks in advance!
function invokeGetMatchingProductForId(MarketplaceWebServiceProducts_Interface $service, $request)
{
try {
$response = $service->GetMatchingProductForId($request);
echo ("Service Response\n");
echo ("=============================================================================\n");
global $file_name;
global $i;
$dom = new DOMDocument();
$dom->loadXML($response->toXML());
$dom->preserveWhiteSpace = false;
$dom->formatOutput = true;
echo $dom->saveXML();
$dom ->save('xml/' . $file_name . $i . '.xml');
echo("ResponseHeaderMetadata: " . $response->getResponseHeaderMetadata() . "\n");
} catch (MarketplaceWebServiceProducts_Exception $ex) {
echo("Caught Exception: " . $ex->getMessage() . "\n");
echo("Response Status Code: " . $ex->getStatusCode() . "\n");
echo("Error Code: " . $ex->getErrorCode() . "\n");
echo("Error Type: " . $ex->getErrorType() . "\n");
echo("Request ID: " . $ex->getRequestId() . "\n");
echo("XML: " . $ex->getXML() . "\n");
echo("ResponseHeaderMetadata: " . $ex- >getResponseHeaderMetadata() . "\n");
}
}
When I get a response from the server, This error occurs.
Fatal error: Cannot redeclare function()(previously declared in x:\xampp\htdocs\name\src\project0\php\unknown.php:110) in x:\xampp\htdocs\name\src\project0\php\unknown.php on line 136
Line 136 is an empty line.