# how to change the value set by the addFixing method in QuantLib

Suppose we have had constructed an index for forecasting future interests of a floating bond, and as suggested by the official document, I used addFixing method to set a past fixing for the current coupon. What I confused was when I reset the addFixing value the program returned an error which says "At least one duplicated fixing provided: ..." . To solve this problem, I backed to check the source code and api doc, and found that there is a parameter called forceOverwrite which seems to be what I need, but when I changed the default value to True, the program told me that "addFixing() got an unexpected keyword argument 'forceOverwrite'". So, is it a bug in QuantLib-Python? If not, what should I do to change the value after having calling addFixing once. Thanks!

flat_forward = FlatForward(Date(8, 5, 2017), 0.04, Actual360(), Compounded, Quarterly)

A note: the parameter will be exposed, but due to the machinery used by SWIG to generate wrappers you probably won't be able to pass it as a keyword argument. Instead of forceOverwrite=True, just pass True.