docs: def _forward_mode(self, *args):
          """Forward mode differentiation for a constant"""
          # Evaluate inner function self.f
          X: np.ndarray
          dX: np.ndarray
          X, dX = self.f._forward_mode(*args)
          # Alias the power to p for legibility
          p: float = self.p
          # The function value
          val = X ** p
          # The derivative
          diff = p * X ** (p-1) * dX
          return (val, diff)