Python Panda Concatenate Row and Constant With lamda and Apply()

Question

I can't figure it out...why it won't work for me.

Given that df:

Product	Final Code	Local Market Code	Import Market Code	Is_import
Chair	I-^placeholder^-23242	sistrix	trixsis	1
Desk	I-^placeholder^-43343	sistrix	trixsis	0
Sofa	I-^placeholder^-5454	gitrix	trixsis	0
Table	I-^placeholder^-545454	gitrix	trixgit	1
Trash Can	I-^placeholder^-545344	gitrix	trixgit	0
Rocking Chair	I-^placeholder^-545454	sistrix	trixgit	1

I need to replace the ^placeholder^ with Import Market Code row and add a "g-" prefix to tha code if Is_import = 1, else Local Market Code.

Without the "g-" constant, it is working great:

new_df['Final Code']=new_df.apply(
                  lambda row: 
row['Final Code'].replace('^placeholder^',row['Import Market Code']) if (row['Is_import'] == 1)
else
row['Final Code'].replace('^pubExternalId^',row['Local Market Code'])
            ,axis=1)

but when concatenating "g-" constant, it won't add the constant:

new_df['Final Code']=new_df.apply(
                  lambda row: 
row['Final Code'].replace('^placeholder^',f"g-{row['Import Market Code']}") if (row['Is_import'] == 1)
else
row['Final Code'].replace('^pubExternalId^',row['Local Market Code'])
            ,axis=1)

or in this form:

new_df['Final Code']=new_df.apply(
                  lambda row: 
row['Final Code'].replace('^placeholder^',"g-"+row['Import Market Code']) if (row['Is_import'] == 1)
else
row['Final Code'].replace('^pubExternalId^',row['Local Market Code'])
            ,axis=1)

Any idea why?

Thanks