code: def uflat(self):
            # noqa
          aligned_arrays = [self[key].values[[(slice(None)
                                               if c in coords
                                               else None)
                                              for c in self._coords]].T
                            for key, coords in self.dependent_variables_info]
          return np.vstack(aligned_arrays).flatten("F")
docs: return a flatten **copy** of the main numpy array with only the
          dependant variables.
  
          Be carefull, modification of these data will not be reflected on
          the main array!