[NEST Users] How to use the update block in NESTML?

Hello, We are trying to plot an exponential synaptic trace in a custom made synapse model made with NESTML, and to do that we are trying to use the print function within the model. But when we try to print something or to change the value of a variable (initialized in the state block) inside the update block, nothing happens. We started with a simple string "Hello", and nothing was printed. We then tried to add 1 to a variable initialized to 0 and its value didn't change. If the print command is written in the onReceive block, it works without problems; as for the variable, its value can be changed in the onReceive block, but if we print its value in the onReceive block and change the value in the update block, we see that the value is not updated from 0. Since we would like to get the value of the synaptic trace to plot its change during simulation, we would need to get the value of the trace not just when a spike is received (there would be no point) but more often. Do you know what we could do? (And why the update block is not working properly?) Best regards, Léa D.