human
Solve the following python programming problem given the following code:
def lazytheanofunc(on_unused_input = 'warn', mode = 'FAST_RUN') : 
    def theanofunction(* args, **kwargs) : 
        f = [None] 
        if (not kwargs.has_key ('on_unused_input')) : 
            kwargs ['on_unused_input'] = on_unused_input 
if (not kwargs.has_key ('mode')) : 
            kwargs ['mode'] = mode 
def func(* args2, **kwargs2) : 
            if (f [0] == None) : 
                f [0] = theano.function (* args, ** kwargs) 
return f [0] (* args2, ** kwargs2) 
return func 
return mode 

    
    

    Fix the buggy line: return mode
assistant
#Here is Python program to fix the buggy line: return mode
.

return def theanofunction(