How to config pact environment

[BitMaster001]

Hello everyone.

I'm using ubuntu 20.04 and installed pact following this link: https://docs.kadena.io/learn-pact/beginner/atom-sdk

But when I run the command pact> (load "hello-world.repl"), I got the following error message.

keysets.pact:2:0: Cannot define a keyset outside of a namespace
 at keysets.pact:2:0: (define-keyset "keyset-carol" (native `read-keyset`  Read KEY from message data ...)

I think there was a problem in installing pact, but I don't know how to resolve this issue.