Syntax to use Python for renaming variables

I am working with a very large dataset and I plan to merge in more years of similar data; however, the data will be panel data so I need to rename the variables with a suffix. I have worked all day on writing script (even started renaming each individual variable but gave up at #409 out of 1300). I have never called upon Python, but I have the following code that I would really appreciate someone double checking. I continue to get a syntax error, and I think it is on the line with myvar = myvar+"_75" or on the line where I close with the three quotes. Thanks in advance! I am on the verge of going syntax-crazy!:confused:

begin program.
import spss, spssaux
spssaux.OpenDataFile ("C:\Users\truji_000\Desktop\ResidentialStability\AHS75.sav")
mylist=vdict.range(start="RURREC" , end="NCLUS")
nvars = len(mylist)

for i in range(nvars) :
myvar = mylist
mynewvar = myvar+"_75"
spss.Submit( r """
rename variables ( %s = %s) .
""" % (myvar, mynewvar))
end program.