from typing import Optional
from typing import Any


def extract_event_description(event) -> Optional[Any]:
    """Helper function to extract event description.

    Args:
        event (dict): Full event data return from API.

    Returns:
        str: event description if exists, else: None.
    """
    event_description = None
    if event.get('Description'):
        event_description = event.get('Description')

    elif event.get('Phrase'):
        event_description = event.get('Phrase')

    elif event.get('Summery'):
        event_description = event.get('Summery')
    return event_description