docs: def set_q1q2(self, q1, q2, check=False):
          """Set upper and lower layer PV anomalies.
  
          Parameters
          ----------
  
          q1 : array-like
              Upper layer PV anomaly in spatial coordinates.
          q1 : array-like
              Lower layer PV anomaly in spatial coordinates.
          """
          self.set_q(np.vstack([q1[np.newaxis,:,:], q2[np.newaxis,:,:]]))
          #self.q[0] = q1
          #self.q[1] = q2
  
          # initialize spectral PV
          #self.qh = self.fft2(self.q)
  
          # check that it works
          if check:
              np.testing.assert_allclose(self.q1, q1)
              np.testing.assert_allclose(self.q1, self.ifft2(self.qh1))