lookupReference method in my ReferenceGroup

I override this lookupReference method in my ReferenceGroup. 

public Common lookupReference()
{
//FormReferenceControl _formReferenceControl;
SysReferenceTableLookup sysTableLookup = SysReferenceTableLookup::newParameters(tableNum(myTable), this);

Query testQuery;
QueryBuildDataSource qbds;

QueryBuildRange qbr;

Common selectedRecord;

str test;

// Display the coulmns fields in the lookup form.
testQuery= new Query();
//test = strFmt('(%1 == Final)',fieldStr(myTable, ProductTypeID));

//sysTableLookup.addLookupfield(fieldNum(myTable, RecId));
// sysTableLookup.addLookupfield(fieldNum(myTable, ProductTypeName));
sysTableLookup.addLookupfield(fieldNum(myTable, ProductTypeID));

// Create a custom Query
qbds = testQuery.addDataSource(tableNum(myTable));

qbds.addRange(fieldnum(myTable, ProductTypeID)).value('Final');

sysTableLookup.parmQuery(testQuery);

selectedRecord = sysTableLookup.performFormLookup();

return sysTableLookup.performFormLookup();

//return sysTableLookup.performFormLookup();
}