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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 fermi_fourier_trans_inverse_4(qubits):
 """The reverse fermionic Fourier transformation implemented on 4 qubits on a line, which maps the momentum picture to the position picture. Using the fast Fourier transformation algorithm, the circuit can be decomposed into 2-mode fermionic Fourier transformation, the fermionic SWAP gates, and single-qubit rotations. Args: qubits: list of four qubits """


    yield fswap(qubits[1], qubits[2]),
    yield fermi_fourier_trans_2(qubits[0], qubits[1])
    yield fermi_fourier_trans_2(qubits[2], qubits[3])
    yield fswap(qubits[1], qubits[2])
    yield fermi_fourier_trans_2(qubits[0], qubits[1])
    yield cirq.S(qubits[2])
    yield fermi_fourier_trans_2(qubits[2], qubits[3])
    yield fswap(qubits[1], qubits[2])