public static SafeFunc <T> operator -(SafeFunc <T> a, Func <T> b)
{
SafeFunc <T> res = new SafeFunc <T>();
res.act = a.act - b;
return(res);
}
public static SafeFunc <T> operator +(SafeFunc <T> a, Func <T> b)
{
a.act -= b;
SafeFunc <T> res = new SafeFunc <T>();
res.act = a.act + b;
return(res);
}