my $defaults = get_defaults();

my $argv = config_from_ARGV( \@ARGV );
my $config_file = $argv->{config_file} || 'myconfig.yml';
my $file = config_from_file( $config_file );
my $env  = config_from_ENV( \%ENV );

# Merge the things
my $final_config = $defaults;
for my $cfg ($config_file, $env, $argv) {
    for my $entry (keys %$cfg) {
        if(defined $cfg->{$entry}) {
            $final_config->{ $entry } = $cfg->{ $entry };
        };
    };
};