When I use VIM via terminal, I keep getting duplicate files with a ~ appended to the end. What are these?

When I use VIM via terminal, I keep getting duplicate files with a ~
appended to the end. What are these?

For example, I'll use VIM to code a Python script and then save the file.
When I navigate to the directory I saved in and use the ls command, up comes:
test_file.py
test_file.py~
Are these backup files?