Are you sure are you running your commands / code in separate lines?

!pip install google-adk -q
!pip install litellm -q
print("Installation complete.")

The first line !pip install google-adk -q will execute the pip install command for the google-adk package with the -q (quiet) flag.

Once that installation is complete, the second line !pip install litellm -q will execute the pip install command for the litellm package with the -q flag.