How to realize implement the Prepared_MPS without auxiliary qubits

[1996ZTR]

INPUT:
A (list): list of N MPS tensors of size (d,chi,chi)
phi_initial (vector): right boundary condition of size (chi,1)
phi_final (vector): left boundary condition of size (chi,1)
keep_ancilla (bool, optional):  the MPS is generated via an ancilla
                                that disentangles at the end of the
                                procedure. By default, the ancilla is
                                measured out and thrown away at the end.
                                Set to True to keep the ancilla
                                (in the first ceil(log(chi)) qubits)