python code use the multi process to consume message from the pika queue by its callback, and listen to keyboard interrupt to stop all processes.
Here is an example of Python code that uses the `multiprocessing` module to consume messages from a RabbitMQ queue using Pika, and listens for keyboard interrupts to stop all processes:
```
import pika
import multiprocessing
import signal
import sys

# Define the callback function to process messages
def process_message(ch, method, properties, body):
    print(f"Received message: {body}")
    # Process the message here
    #...

# Define the worker function to consume messages from the queue
def worker(queue_name, num_processes):
    connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
    channel = connection.channel()
    channel.queue_declare(queue=queue_name)

    def callback(ch, method, properties, body):
        process_message(ch, method, properties, body)

    channel.basic_consume(queue=queue_name, on_message_callback=callback, auto_ack=True)

    print(f"Worker {num_processes} started consuming from queue {queue_name}")
    while True:
        connection.process_data_events()

# Define the main function to start multiple workers
def main():
    queue_name = "my_queue"
    num_workers = 5

    # Create a list to store the worker processes
    workers = []

    # Start the workers
    for i in range(num_workers):
        p = multiprocessing.Process(target=worker, args=(queue_name, i))
        workers.append(p)
        p.start()

    # Listen for keyboard interrupts
import pika 
import threading 
import time 

# Establish a connection to the Pika Queue
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost')) 

# Consume messages from the queue 
channel = connection.channel() 

# Consume messages from the queue 
channel.basic_consume(lambda message: print(message), queue="my_queue") 

# Start consuming messages from the queue 
channel.start_consuming() 

# Listen to keyboard interrupt to stop all processes 
def key_interrupt_handler(): 
    connection.stop_consuming() 
    connection.close() 
    threading.Thread(target=key_interrupt_handler).start() 

# Start listening to keyboard interrupt 
keyboard_interrupt = input("Press <Enter> to stop all processes: ")
keyboard_interrupt_handler()