Shared preferences in flutter

// SAVING DATA
saveString(key, value) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  prefs.setString(key, value);
}

saveDouble(key, value) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  prefs.setDouble(key, value);
}

saveInt(key, value) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  prefs.setInt(key, value);
}

saveBool(key, value) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  prefs.setBool(key, value);
}


// RETRIEVING DATA
retrieveString(key) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  //Return String
  String stringValue = prefs.getString(key);
  return stringValue;
}

retrieveDouble(key) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  //Return double
  double doubleValue = prefs.getDouble(key);
  return doubleValue;
}

retrieveInt(key) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  //Return int
  int intValue = prefs.getInt(key);
  return intValue;
}

retrieveBool(key) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  //Return bool
  bool boolValue = prefs.getBool(key);
  return boolValue;
}


// DELETING DATA
removeValues() async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  //Remove String
  prefs.remove("stringValue");
  //Remove bool
  prefs.remove("boolValue");
  //Remove int
  prefs.remove("intValue");
  //Remove double
  prefs.remove("doubleValue");
}


// CHECKING DATA
bool CheckValue = prefs.containsKey('value');