BER Curve Gen GNURADIO and others questions

[JORGE GONZALEZ ORELLANA]

Hi everyone, i have been trying to implement OFDM on the GRC (v3.8.5.0) so far i have this thanks to the examples that come with the companion:

What I want it's to create a BER/Snr curve, at this point, I have only been able to use the BER block in a number sink, but here it is when I have problems.

1.-  The ber_curve_gen example comes with a problem, it says:  Value "list(map(lambda b:list(map(lambda a:b * len(esno) * 2 + a, range(num_curves)))" cannot be evaluated: name 'num_curves' is not defined. In the QT GUI Bercurve Sink block on the "Num_curves" variable there is a number, so I am not really sure what is happening.

2.- in general i don't really understand what is happening in the ber_curve_gen example and if anyone could explain to me briefly, that would be great.

Thanks for your time, i really appreciate your answers