Just to point out that the rational resampler block in gnuradio
3.7. of gnuradio companion has a default for Taps to be
‘None’. This isn’t a legal option - the default in pre-3.7 versions
was a blank. If the value of None is used you get there error message:
Param - Taps(taps):
Expression “[None]” is invalid for type float vector.
I suggest change the default back to blank/empty.