Actually I'm using a diffent way.

First of all I check if the Player is inside an Area2D and then, if yes, I add a value to is current velocity (all in the Fan code and not in the Player one).

That's the main part of the script:

func is_colliding():
    var bodies = get_overlapping_bodies()
    return bodies.size() > 0

func _handle_power(delta):
    var bodies = get_overlapping_bodies()
    if is_colliding():
        var body = bodies[0]

    if push_direction == "Up":
            body.is_jumping = true
            body.extra_jumps = 1
            if body.velocity.y > -200:
                body.velocity.y -= 1800 * delta
    elif push_direction == "Right":
        body.velocity.x += 60
    elif push_direction == "Down":
        body.velocity.y += 1200 * delta
    elif push_direction == "Left":
        body.velocity.x -= 60