Convert a LocalOperator instance to qutip

def _convert_local_operator_to_qutip(expr, full_space, mapping):
    """Convert a LocalOperator instance to qutip"""
    n = full_space.dimension
    if full_space != expr.space:
        all_spaces = full_space.local_factors
        own_space_index = all_spaces.index(expr.space)
        return qutip.tensor(
            *([qutip.qeye(s.dimension)
               for s in all_spaces[:own_space_index]] +
              [convert_to_qutip(expr, expr.space, mapping=mapping), ] +
              [qutip.qeye(s.dimension)
               for s in all_spaces[own_space_index + 1:]])
        )
    if isinstance(expr, Create):
        return qutip.create(n)
    elif isinstance(expr, Jz):
        return qutip.jmat((expr.space.dimension-1)/2., "z")
    elif isinstance(expr, Jplus):
        return qutip.jmat((expr.space.dimension-1)/2., "+")
    elif isinstance(expr, Jminus):
        return qutip.jmat((expr.space.dimension-1)/2., "-")
    elif isinstance(expr, Destroy):
        return qutip.destroy(n)
    elif isinstance(expr, Phase):
        arg = complex(expr.operands[1]) * arange(n)
        d = np_cos(arg) + 1j * np_sin(arg)
        return qutip.Qobj(np_diag(d))
    elif isinstance(expr, Displace):
        alpha = expr.operands[1]
        return qutip.displace(n, alpha)
    elif isinstance(expr, Squeeze):
        eta = expr.operands[1]
        return qutip.displace(n, eta)
    elif isinstance(expr, LocalSigma):
        j = expr.j
        k = expr.k
        if isinstance(j, str):
            j = expr.space.basis_labels.index(j)
        if isinstance(k, str):
            k = expr.space.basis_labels.index(k)
        ket = qutip.basis(n, j)
        bra = qutip.basis(n, k).dag()
        return ket * bra
    else:
        raise ValueError("Cannot convert '%s' of type %s"
                         % (str(expr), type(expr)))