dora/runtime/examples/python-operator/op.py

class Operator:
    def __init__(self, counter=0):
        self.counter = counter
    
    def on_input(self, id, value, send_output):
        val_len = len(value)
        print(f'PYTHON received input {id}; value length: {val_len}')
        send_output("counter", self.counter.to_bytes(1, 'little'))
        self.counter = (self.counter + 1) % 256