Reduce the alist dimension if needed

def _simplify_shape(self, alist, rec=0):
        """Reduce the alist dimension if needed"""
        if rec != 0:
            if len(alist) == 1:
                return alist[-1]
            return alist
        if len(alist) == 1:
            return self._simplify_shape(alist[-1], 1)
        return [self._simplify_shape(al, 1) for al in alist]