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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def set_dtreat_interp_indch(self, indch=None):
 """ Set the indices of the channels for which to interpolate data The index can be provided as: - A 1d np.ndarray of boolean or int indices of channels => interpolate data at these channels for all times - A dict with: * keys = int indices of times * values = array of int indices of chan. for which to interpolate Time indices refer to self.ddataRef['t'] Channel indices refer to self.ddataRef['X'] """

        lC = [indch is None, type(indch) in [np.ndarray,list], type(indch) is dict]
        assert any(lC)
        if lC[2]:
            lc = [type(k) is int and k<self._ddataRef['nt'] for k in indch.keys()]
            assert all(lc)
            for k in indch.keys():
                assert hasattr(indch[k],'__iter__')
                indch[k] = _format_ind(indch[k], n=self._ddataRef['nch'])
        elif lC[1]:
            indch = np.asarray(indch)
            assert indch.ndim==1
            indch = _format_ind(indch, n=self._ddataRef['nch'])
        self._dtreat['interp-indch'] = indch
        self._ddata['uptodate'] = False