def truthy_indicies(lhs, ctx):
    """Element T
    (any) -> indicies of truthy elements
    (num) -> lhs * 3
    """

    if vy_type(lhs) == NUMBER_TYPE:
        return lhs * 3

    lhs = iterable(lhs, ctx=ctx)

    @lazylist
    def helper():
        for i in range(len(lhs)):
            if lhs[i]:
                yield i

    return helper()

def pi_digits(x: int):
    """Generate x digits of Pi. Spigot's formula."""
    @lazylist
    def gen():
        # code
    return gen()

def pi_digits(x: int):
    """Generate x digits of Pi. Spigot's formula."""
    def gen():
        # code
    return LazyList(gen())

"∆I": process_element("pi_digits(lhs)", 1),

arg1, arg2, arg3 = pop(stack, 3, ctx=ctx)
stack.append(subtract(arg1,multiply(add(arg2, arg3), 5))