def METHOD_NAME(self, blinding_key):
    # either WIF or hex
    try:
        bkey = ec.PrivateKey.from_string(blinding_key)
    except:
        bkey = ec.PrivateKey.parse(bytes.fromhex(blinding_key))
    self.blinding_key = str(bkey)
    write_json_file(self.json, self.fullpath)
    self.manager.update()