Please configure your AWS credentials, either through environment variables or
~/.aws/credentials config file.

For example:

export AWS_ACCESS_KEY_ID=XXXXXXXXXXXXXX
export AWS_SECRET_ACCESS_KEY=XXXXXXXXXXXXXXXXXXXXXXXXXXXXX

or in ~/.aws/credentials (make sure you chmod 600 ~/.aws/credentials):

[default]
aws_access_key_id = AKID1234567890
aws_secret_access_key = MY-SECRET-KEY

You can switch between different sets in the credentials file by passing
--profile to any command, or setting the environment variable AWS_PROFILE.

For example:
    cli53 list --profile my_profile