Recall that the producer price index is of interest primarily for its eventual impact on consumer prices. See if the (Michal) Kalecki model shows this. Write out the equation for consumer prices (the one we derived in class that had the markup-you can jump right to it, you don't have to derive it) and then figure out if and where producer prices (P_I) would show up in there (you should be able to substitute it in somewhere). Do you find that changes in P_I affect P_C and if so, how (i.e., do they move in the same or opposite directions) and is this what you would expect? A brief answer would be better.