public BuildParameterBuilder addConfigIfExists(String pathToConfig) {
        if (pathToConfig == null || pathToConfig.isEmpty()) {
            return this;
        } else if (!Files.exists(Paths.get(pathToConfig))) {
            LOGGER.info("Not setting --config to " + pathToConfig + " because it does not exist");
            return this;
        }

        return addConfig(pathToConfig);
    }
Adds a configuration file to the builder only if it exists.

<p>This method is ignored if the file is null, empty, or does
not exist.

@param pathToConfig Path to the configuration file.
@return Returns the builder.
smithy-cli/src/main/java/software/amazon/smithy/cli/BuildParameterBuilder.java