`NameError` in `freegs4e.jtor` when using `GeneralPprimeFFprime`

[theo-brown]

When writing to geqdsk, I get a NameError when eq.fpol is called:

~/open-step/.venv/lib64/python3.12/site-packages/freegs4e/geqdsk.py:94, in write(eq, fh, label, oxpoints, fileformat)
     88 data["cpasma"] = eq.plasmaCurrent()  # Plasma current [A]
     90 psinorm = linspace(
     91     0.0, 1.0, nx, endpoint=False
     92 )  # Does not include separatrix
---> 94 data["fpol"] = eq.fpol(psinorm)
     95 data["pres"] = eq.pressure(psinorm)
     96 data["ffprime"] = eq.ffprime(psinorm)

File ~/open-step/.venv/lib64/python3.12/site-packages/freegs4e/equilibrium.py:738, in Equilibrium.fpol(self, psinorm)
    722 def fpol(self, psinorm):
    723     """
    724     Return f = R*Bt at specified values of normalised psi (i.e.
    725     inside the plasma core).
   (...)    735         fpol at values of normalised psi [Tm].
    736     """
--> 738     return self._profiles.fpol(psinorm)

File ~/open-step/.venv/lib64/python3.12/site-packages/freegs4e/jtor.py:1805, in GeneralPprimeFFprime.fpol(self, pn)
   1803     return self.f_func(pn_)
   1804 else:
-> 1805     return super(GeneralPprimeFfprime, self).fpol(pn_)

NameError: name 'GeneralPprimeFfprime' is not defined