static LevelFiller parseLevelParameter(String wrappedParameter, String trimmedParameter) {
        if (trimmedParameter.equals(PARAMETER_LEVEL_SHORT)) {
            return new LevelFiller(wrappedParameter, trimmedParameter, false);
        } else if (trimmedParameter.equals(PARAMETER_LEVEL_LONG)) {
            return new LevelFiller(wrappedParameter, trimmedParameter, true);
        }
        return null;
    }
Try to create a level filler if the given parameter is a level parameter.

@return created level filler, or null if the given parameter is not a level parameter
android/android_framework/base/src/main/java/com/elvishew/xlog/flattener/PatternFlattener.java