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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 concat_t_vars(self):
 """ Concatenate ``self.t`` with ``self.vars`` and output a single matrix for data dump :return matrix: concatenated matrix with ``self.t`` as the 0-th column """

        logger.warning('This function is deprecated and replaced by `concat_t_vars_np`.')
        out = np.array([])

        if len(self.t) == 0:
            return out

        out = np.ndarray(shape=(0, self.vars[0].size[0] + 1))

        for t, var in zip(self.t, self.vars):
            line = [[t]]
            line[0].extend(list(var))
            out = np.append(out, line, axis=0)

        return out