(Solved)Air SDK 7.1 Installation issue

When installing Air SDK 7.1, I encountered the following error when performing apt-get update.

Error: 9 ftp://ftp2.parrot.biz/dev focal / Release
Unable to get the file. Server response Can’t open / dev / focal / Release: No such file or directory

E: There is no Release file in the repository ftp://ftp2.parrot.biz/dev focal / Release.

What should i do?

Sorry, It was caused by a typo.
I modified dev to deb and it worked.