arduino int data;

void setup()
{
  Serial.begin(9600);
  pinMode(2, OUTPUT);
  digitalWrite (2, LOW); //initially set to low   //Sets up all the pins for use
  pinMode(3, OUTPUT);
  digitalWrite (3, LOW); //initially set to low
  pinMode(4, OUTPUT);
  digitalWrite (4, LOW); //initially set to low
  pinMode(5, OUTPUT);
  digitalWrite (5, LOW); //initially set to low
  pinMode(6, OUTPUT);
  digitalWrite (6, LOW); //initially set to low
  pinMode(7, OUTPUT);
  digitalWrite (7, LOW); //initially set to low
  pinMode(8, OUTPUT);
  digitalWrite (8, LOW); //initially set to low
  pinMode(9, OUTPUT);
  digitalWrite (9, LOW); //initially set to low
}

void loop()
{
while (Serial.available())                            //receives data from python script
  {
    data = Serial.read();                             //stores data in a variable
  }
  //LED ON
  if (data == '1'){                                   //reads data and lights an LED
  digitalWrite (2, HIGH);
  }
  if (data == '2'){
  digitalWrite (3, HIGH);
  }
  if (data == '3'){
  digitalWrite (4, HIGH);
  }
  if (data == '4'){
  digitalWrite (5, HIGH);
  }
  if (data == '5'){
  digitalWrite (6, HIGH);
  }
  if (data == '6'){
  digitalWrite (7, HIGH);
  }
  if (data == '7'){
  digitalWrite (8, HIGH);
  }
  if (data == '8'){
  digitalWrite (9, HIGH);
  }
  //LED OFF
  if (data == 'a')                                  //reads data and lights an LED
  digitalWrite (2, LOW);
  if (data == 'b')
  digitalWrite (3, LOW);
  if (data == 'c')
  digitalWrite (4, LOW);
  if (data == 'd')
  digitalWrite (5, LOW);
  if (data == 'e')
  digitalWrite (6, LOW);
  if (data == 'f')
  digitalWrite (7, LOW);
  if (data == 'g')
  digitalWrite (8, LOW);
  if (data == 'h')
  digitalWrite (9, LOW);

}