Ghidra Python, creating a memory reference to an already defined string

Ghidra 10.3 and MS-DOS 16-bit executables. I'm having trouble figuring out how to script creating memory references. The goal is to locate patterns for MOV DX,VALUE then create a memory reference for VALUE if it's validated as the location of a string. I have everything working except creating the actual reference.

This line for example.

MOV DX,0x12b1

I want the same result as right clicking the value (0x12b1) and selecting Create Memory Reference.

I think my issue is misunderstanding this line...

createMemoryReference(data, addr, ghidra.program.model.symbol.RefType.DATA)

...in my function below.

def tryRefStr(address):
    result = False
    opcode = getByteAt(address)
    if opcode == opcodeMovDX:       
        valu = getWordAt(address.add(1))        #hex value (0x12b1)
        addr = getAddress(valu)                 #hex value as address object
        data = listing.getDefinedDataAt(addr)   #data object from 0x12b1 (the string)
        if data is not None:            
            dtyp = data.getDataType()           #datatype of the object at 0x12b1
            if str(dtyp) == 'string':           #see if it's a string (crude, I know)
                result = True
                createMemoryReference(data, addr, ghidra.program.model.symbol.RefType.DATA)
    return result

Instead of replacing VALUE in MOV DX,VALUE with a memory reference to 0x12b1 it creates a reference at the string's location instead, or something of that nature. I don't understand enough to explain exactly what it's doing.

I figured it out through trial and error.

The result I wanted is achieved with...

instr = listing.getInstructionContaining(addr)
instr.addOperandReference(1, addr, RefType.DATA, SourceType.ANALYSIS)

Instead of...

createMemoryReference(data, addr, RefType.DATA)