[Discuss-gnuradio] how to use value of a variable_sink in program

[nansai hu]

how to use value of a variable_sink in program?

I use a variable_sink to receive a value that clac in GRC program
Now I want to use this value in another place in program(name as val_freq),

So how to do that? I announced val_freq in front of whole program and add two yellow lines in variable_sink,
but it doesn't work.

self.blks2_variable_sink_x_0 = grc_blks2.variable_sink_f(
            vlen=1,
            decim=1,
            callback=self.set_mod_freq_sg,
            global val_freq
            val_freq=self.set_mod_freq_sg,
        )