campaign impression metrics script is not overwriting the database values for Google

Steps:
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1. Run the get-campaign-impression-metrics.sh script for a performance account.
2. Compare the database values with Google AdWords.
3. Update the database values to some other values.
4. Rerun the get-campaign-impression-metrics.sh script again for the same account.

Expected: The script should overwrite the database values with the values in Google AdWords.

Actual: It was not overwriting the database values with the values in AdWords.

Note: When we re-run the same script 2nd time, values are overwritten.

See the attached log when the script was rerun for first time.