stagedUploadsCreate error with shopify api node

Hello I have install the shopify api node package version 3.15.0.

When I send the StagedUploadCreate Mutation i get the error:
RequestError: Variable $input of type [StagedUploadInput!]! was provided invalid value

I don’t find the mistake, here the code:

let input = [];

for await (const [i, jsonlFileContent] of jsonlFileContentList.entries()) {

console.log("Creating staged file for batch:", i);

// Fill input for staged upload mutation    

input.push(
{

resource: "BULK_MUTATION_VARIABLES",

filename: `bulk_op_vars_${i}.jsonl`,

mimeType: "text/jsonl",

httpMethod: "POST"

  }

);
}

console.log(input);

// Create temporary shopify file.

response = await shopify.graphql(

`#graphql

mutation stagedUploadsCreate($input: [StagedUploadInput!]!) {

stagedUploadsCreate(input: $input) {

stagedTargets {

url

resourceUrl

parameters {

name

value

                            }

                        }

userErrors {

field

message

                        }

                        }

                    }

`,

                {

variables: {

input: input

                    }

                }

            );

resource appears to be an enum, can you try it without the quotes around BULK_MUTATION_VARIABLES?

without the quotes I get: ReferenceError: BULK_MUTATION_VARIABLES is not defined

let response = await shopify.graphql(

                `#graphql

mutation stagedUploadsCreate($input: [StagedUploadInput!]!) {

stagedUploadsCreate(input: $input) {

stagedTargets {

url

resourceUrl

parameters {

name

value

                            }

                        }

userErrors {

field

message

                        }

                        }

                    }

`,

                    {

input: input

                    }

            );