$GOOGLE_CLOUD_BUCKET_NAME is undefined while running colab

I am new to colab & xmanager on gcp.

I have tried to set GOOGLE_CLOUD_BUCKET_NAME by running
`! export GOOGLE_CLOUD_BUCKET_NAME=my_bucket_name`
I tried prefixing 'gs://' with my_bucket_name
but it keeps failing with the following error:
`ValueError: $GOOGLE_CLOUD_BUCKET_NAME is undefined. Run export GOOGLE_CLOUD_BUCKET_NAME=, replacing with a Google Cloud Storage bucket. You can create a bucket with gsutil mb -l us-central1 gs://$GOOGLE_CLOUD_BUCKET_NAME`

I have enabled vertexAI & I have created a google cloud storage bucket.
running `!echo $GOOGLE_CLOUD_BUCKET_NAME` also returns empty