import re
from datetime import datetime, timedelta
from typing import Union


def extract_emails(field: str):
    matches = re.findall(r'([a-zA-Z0-9+._-]+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9_-]+)', field.lower())
    return tuple({str(x) for x in matches})


def unix_timestamp_since_to_imap_timestamp(unix_timestamp: Union[int, float]) -> str:
    return (datetime.fromtimestamp(unix_timestamp) - timedelta(days=1)).strftime("%d-%b-%Y")