How to mock SLI availability success ratio in Python

import random
from collections import defaultdict

def mock_availability(num_requests=1000, target_ratio=0.995):
    """
    Simulate request outcomes and compute the SLI availability success ratio.
    
    Args:
        num_requests: Total number of requests to simulate
        target_ratio: Target availability ratio (e.g., 0.995 = 99.5%)
    
    Returns:
        Tuple of (successful_requests, total_requests, availability_ratio)
    """
    random.seed(42)  # Deterministic for reproducibility
    outcomes = defaultdict(int)
    
    for _ in range(num_requests):
        # Simulate a request: succeed with probability based on target
        if random.random() < target_ratio:
            outcomes["success"] += 1
        else:
            outcomes["failure"] += 1
    
    successful = outcomes["success"]
    total = num_requests
    ratio = successful / total
    
    return successful, total, ratio

if __name__ == "__main__":
    success_count, total_requests, ratio = mock_availability()
    print(f"Successful requests: {success_count}/{total_requests}")
    print(f"Availability ratio: {ratio:.4f} ({ratio*100:.2f}%)")
    print(f"Target ratio met: {ratio >= 0.995}")