Connect Rotary Encoder with Python via Arduino - python-2.7

Question

For a project I am working on I need to connect a rotary encoder to my Arduino Mega(2560) board. The rotary encoder will act as a sort of very precise scrolling wheel to position an object in my python code. I found this Arduino code which does very nicely what I want. However, in order to implenemt the encoder readout in python I somehow need to "connect" my Input I recieve from the Arduino board to my Python Code. I tried to somehow "convert" the Arduino code into Python code and came across the idependencies of pySerial and pyfirmata which looked promising. yet, there are certain functions in the Arduino that are not mimicked by Python, such as the attachInterrupt() function or volatile unsigned int.
I was hoping someone could point me in the right direction of to convert the following Arduino code for the rotary encoder into Python code.
// Encoder connect to digitalpin 2 and 3 on the Arduino.
volatile unsigned int counter = 0; //This variable will increase or decrease depending on the rotation of encoder
void setup() {
Serial.begin (9600);
//Setting up interrupt
//A rising pulse from encodenren activated ai0(). AttachInterrupt 0 is DigitalPin nr 2 on moust Arduino.
attachInterrupt(0, ai0, RISING);
//B rising pulse from encodenren activated ai1(). AttachInterrupt 1 is DigitalPin nr 3 on moust Arduino.
attachInterrupt(1, ai1, RISING);
}
void loop() {
// Send the value of counter
Serial.println (counter);
}
void ai0() {
// ai0 is activated if DigitalPin nr 2 is going from LOW to HIGH
// Check pin 3 to determine the direction
if(digitalRead(3)==LOW) {
counter++;
}else{
counter--;
}
}
void ai1() {
// ai0 is activated if DigitalPin nr 3 is going from LOW to HIGH
// Check with pin 2 to determine the direction
if(digitalRead(2)==LOW) {
counter--;
}else{
counter++;
}
}
created 2014
by Ben-Tommy Eriksen
https://github.com/BenTommyE/BenRotaryEncoder
Thank you