sign(1 + x) + sign(-1 + x)
$$\operatorname{sign}{\left(x - 1 \right)} + \operatorname{sign}{\left(x + 1 \right)}$$
2*(DiracDelta(1 + x) + DiracDelta(-1 + x))
$$2 \left(\delta\left(x - 1\right) + \delta\left(x + 1\right)\right)$$
2*(DiracDelta(1 + x, 1) + DiracDelta(-1 + x, 1))
$$2 \left(\delta^{\left( 1 \right)}\left( x - 1 \right) + \delta^{\left( 1 \right)}\left( x + 1 \right)\right)$$