my $cloudwatch = Paws->service('CloudWatch', 
                                caller => $lwp_caller, 
                                credentials => Paws::Credential::AssumeRole->new(
                                    RoleArn => 'arn:aws:iam::MY_IAM_CODE:role/MY_ROLE',
                                    RoleSessionName => 'just_kidding',
                                    #caller => $lwp_caller, 
                                ),
                                region => 'us-east-1', 
                                profile_name => 'instrument',
                              );