'a**(n+m) -> a**n*a**m'

def _eval_expand_power_exp(self, **hints):

    b = self.base
    e = self.exp
    if (e.is_Add and e.is_commutative):
        expr = []
        for x in e.args:
            expr.append(self.func(self.base, x))
        return Mul(*expr)
    return self.func(b, e)
