def METHOD_NAME(self, ix):
    if self.merger is not None:
        ttf = self.merger.ttfs[ix]
        if "name" in ttf and ttf["name"].getBestFullName():
            return ttf["name"].getBestFullName()
        elif hasattr(ttf.reader, "file") and hasattr(ttf.reader.file, "name"):
            return ttf.reader.file.name
    return f"master number {ix}"