code: def get_fn_plan(callback=None, out_callback=None, name='pycbc_cufft', parameters=None):
      
      if parameters is None:
          parameters = []
      source = fftsrc.render(input_callback=callback, output_callback=out_callback, parameters=parameters)
      path = compile(source, name)
      lib = ctypes.cdll.LoadLibrary(path)
      fn = lib.execute
      fn.argtypes = [ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p]
      plan = lib.create_plan
      plan.restype = ctypes.c_void_p
      plan.argyptes = [ctypes.c_uint]
      return fn, plan
docs: Get the IFFT execute and plan functions