GraphQL checkoutLineItemsUpdate

[oleksandr_OD]

Hello. I want to make a mutation, but I keep getting "invalid id" error. What am I doing wrong?

https://shopify.dev/api/storefront/2022-01/mutations/checkoutLineItemsUpdate

{%- for item in checkout.line_items -%}
    {%- if forloop.first -%}
        {%- assign line_item_id = item.id -%}
        {%- assign variant_id = item.variant_id -%}
        {%- assign line_item_qty = item.quantity -%}
    {%- endif -%}
{%- endfor -%}
        fetch('/api/2022-01/graphql.json', {
                method: "POST",
                headers: {
                    "Content-Type": "application/json",
                    "X-Shopify-Storefront-Access-Token": "Token"
                },
            body: JSON.stringify({
                query: "mutation checkoutLineItemsUpdate($checkoutId: ID!, $lineItems: [CheckoutLineItemUpdateInput!]!) {checkoutLineItemsUpdate(checkoutId: $checkoutId, lineItems: $lineItems) { checkout { id } checkoutUserErrors { code }}}",
                variables: {
                    "checkoutId": "gid://shopify/Checkout/{{- checkout.id -}}",
                    "lineItems": {
                        "customAttributes": {
                            "key": "MyKey",
                            "value": "MyValue"
                        },
                        "id": "gid://shopify/LineItem/{{- line_item_id -}}",
                        "quantity": {{- line_item_qty -}},
                        "variantId": "gid://shopify/ProductVariant/{{- variant_id -}}"
                    }
                }
            }),
        })
            .then(response => response.json())
            .then(data => {
                console.log('Success:', data);
            })
            .catch((error) => {
                console.error('Error:', error);
            });
    };