static S loadTextFilePossiblyGZipped(S fileName) {
  ret loadTextFilePossiblyGZipped(fileName, null);
}
  
static S loadTextFilePossiblyGZipped(S fileName, S defaultContents) {
  File gz = new File(fileName + ".gz");
  ret gz.exists() ? loadGZTextFile(gz) : loadTextFile(fileName, defaultContents);
}

static S loadTextFilePossiblyGZipped(File fileName) {
  ret loadTextFilePossiblyGZipped(fileName, null);
}

static S loadTextFilePossiblyGZipped(File fileName, S defaultContents) {
  ret loadTextFilePossiblyGZipped(fileName.getPath(), defaultContents);
}

Began life as a copy of #1001049