How to connect to Google Cloud Storage from Google Cloud Functions NodeJS

I have the following code sample that receives a bufferedImage along with it's mimeType and then uploads it to Google Cloud Storage.

Everything works fine, but for some reason my Google Cloud Function is getting an 403 error from the Storage API.

What do i have to do so that my GC Function has access to GC Storage?

I couldn't find anything in the documentation that would show me how to do this.

const { Storage } = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

// Lists all buckets in the current project
const buckets = storage.getBuckets();

exports.uploadImage = (bucketName, fileName, imageBuffer, mimeType) => {
  return new Promise((resolve, reject) => {

    let bucket = storage.bucket(bucketName);

    let file = bucket.file(fileName);
    file.save(imageBuffer,
        {
            metadata: { contentType: `image/${mimeType}` },
        },
        ((error) => {
            error ? reject(error) : resolve()
        })
    );
  })
}

here is the error I'm getting

{"code":403,"errors":[{"domain":"global","reason":"forbidden","message":"directed-galaxy-221521@appspot.gserviceaccount.com does not have storage.objects.create access to blog/e33f9c9d-65f0-4a7f-8332-29846f770e6d."}],"message":"directed-galaxy-221521@appspot.gserviceaccount.com does not have storage.objects.create access to blog/e33f9c9d-65f0-4a7f-8332-29846f770e6d."}

from How to connect to Google Cloud Storage from Google Cloud Functions NodeJS