# Example of a prompt for complex code generation
prompt = """
Generate a Python class for a distributed rate limiter using a Redis backend.
The class should implement the following methods:
- __init__(self, redis_client, key_prefix, default_rate, default_interval):
    - Initializes the limiter with a Redis client, a prefix for keys,
      and a default rate (requests per interval).
- acquire(self, identifier, rate=None, interval=None):
    - Attempts to acquire a permit for the given `identifier`.
    - Uses `rate` and `interval` if provided, otherwise uses defaults.
    - Returns True if acquired, False otherwise.
    - This should use the sliding window log algorithm with Lua scripting for atomicity.
    - Ensure the script handles Redis connection errors gracefully.
- is_allowed(self, identifier, rate=None, interval=None):
    - Checks if an acquisition would be allowed without actually acquiring.
    - Uses `rate` and `interval` if provided, otherwise uses defaults.
    - Returns True if allowed, False otherwise.

Provide clear docstrings for each method and the class.
Include basic error handling for Redis operations.
"""