'Represents DiracDelta in a Piecewise form
Examples
>>> from sympy import DiracDelta, Piecewise, Symbol, SingularityFunction
>>> x = Symbol(\'x\')
>>> DiracDelta(x).rewrite(Piecewise)
Piecewise((DiracDelta(0), Eq(x, 0)), (0, True))
>>> DiracDelta(x - 5).rewrite(Piecewise)
Piecewise((DiracDelta(0), Eq(x - 5, 0)), (0, True))
>>> DiracDelta(x**2 - 5).rewrite(Piecewise)
Piecewise((DiracDelta(0), Eq(x**2 - 5, 0)), (0, True))
>>> DiracDelta(x - 5, 4).rewrite(Piecewise)
DiracDelta(x - 5, 4)'

def _eval_rewrite_as_Piecewise(self, *args):

    if (len(args) == 1):
        return Piecewise((DiracDelta(0), Eq(args[0], 0)), (0, True))
