Filters added to base_price

It would be great to have opportunity to change $base_price through filters if product price depends on the quantity, for example.
Say, if I ordered {x} units, then the base_price will be 5$. But if I ordered more than {y}, then it will be 3$.

The add_filter function might look like:

```php
add_filter( 'woocommerce_base_price', 'my_base_price', 10, 2);
function my_base_price($price, $cart_item) {
    $product_id   = apply_filters( 'woocommerce_cart_item_product_id', $cart_item['product_id'], $cart_item);
    // x < y
    $product_more_than_x = get_post_meta( $product_id, '_woo_more_than_x', true );
    $product_more_than_y = get_post_meta( $product_id, '_woo_more_than_y', true );

    if ($cart_item['quantity'] >= $product_more_than_y) {
        return get_post_meta( $product_id, '_woo_big_price', true );
    } elseif ($cart_item['quantity'] >= $product_more_than_x) {
        return get_post_meta( $product_id, '_woo_medium_price', true );
    } else {
        return $price;   
    }
}
```