emoji_eventsParse a log file

Given lines from a web server access log, write summarise(lines) that returns a dict with:

• "requests": number of valid lines
• "errors": number of responses with status 500 or above
• "top_path": the most requested path (ties: alphabetically first)
• "bad_lines": number of lines that don't match the format

Line format: IP - - [time] "METHOD /path HTTP/1.1" STATUS BYTES