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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 destruct(particles, index):
 """Fermion annihilation operator in matrix representation for a indexed particle in a bounded N-particles fermion fock space"""


    mat = np.zeros((2**particles, 2**particles))

    flipper = 2**index
    for i in range(2**particles):
        ispin = btest(i, index)
        if ispin == 1:
            mat[i ^ flipper, i] = phase(i, index)
    return csr_matrix(mat)