docs: def build_interpolators(self):
          """Compute 1-D interpolation functions for all the transforms so they're continuous.."""
          self.phi_continuous = []
          for xi, phii in zip(self.ace.x, self.ace.x_transforms):
              self.phi_continuous.append(interp1d(xi, phii))
          self.inverse_theta_continuous = interp1d(self.ace.y_transform, self.ace.y)