I have set up a loop to list csv files and merge their data (approximately 20,000 rows) to a final CSV file using CSV writer. I get the following message:
Execute failed: You are attempting to add an observation for the time period Sun Dec 25 12:09:22 EST 2016 but the series already contains an observation for that time period. Duplicates are not permitted. Try using the addOrUpdate() method.
What is the addOrUpdate() method that I could use to solve this issue?