retrieve the PlayerRecord settings from saved disk file

def load(self, playerName=None):
        """retrieve the PlayerRecord settings from saved disk file"""
        if playerName: # switch the PlayerRecord this object describes
            self.name = playerName # preset value to load self.filename
        try:
            with open(self.filename, "rb") as f:
                data = f.read()
        except Exception:
            raise ValueError("invalid profile, '%s'. file does not exist: %s"%(self.name, self.filename))
        self.update(json.loads(data))
        self._matches = [] # mandate match history be recalculated for this newly loaded player