Can't add and controll my own arguemts to SynthDefs in Tidal?

In tutorial synths.scd in the SuperDirt synths folder I’ve been trying to follow the instruction on adding and playing my own SynthDefs in Tidal. I’ve managed to understand all the examples except for the last one on adding and controlling arguments from tidal.
I can’t figure out why I can’t define the freq in the last example even If I followed the instruction let (f, f_p) = pF “f” I get this error message:

  • Couldn’t match expected type (a, b)' with actual typePattern Double -> ControlPattern’
  • Probable cause: `pF’ is applied to too few arguments
    In the expression: pF “f”
    In a pattern binding: (f, f_p) = pF “f”
  • Relevant bindings include
    f :: a
    f_p :: b

What am I doing wrong? Do I need to recompile the class library in superCollider or do something in Tidal that I don’t know of?