Adding metadata / identifier data to a CSV file?

Question

Is there a way to add a \"tag\" (add a unique metadata/identifier) to a CSV file without affecting the contents or ability to read/write the file?

I am using Python, but

Answer 1

Just add comment lines that you can parse later.

#Creator:JohnSmith
#Date:....
#Columns:id,username,...
1,JohnSmith
2, ..