def timestamp_to_datetime(ts):
    """Converts a timestamp (number of milliseconds since epoch) to a
    `datetime.datetime`.

    Args:
        ts: a number of milliseconds since epoch

    Returns:
        a `datetime.datetime`
    """
    dt = datetime.utcfromtimestamp(ts / 1000.0)

    if fo.config.timezone is None:
        return dt

    timezone = pytz.timezone(fo.config.timezone)
    return dt.replace(tzinfo=pytz.utc).astimezone(timezone)
Converts a timestamp (number of milliseconds since epoch) to a
    `datetime.datetime`.

    Args:
        ts: a number of milliseconds since epoch

    Returns:
        a `datetime.datetime`
    
fiftyone/core/utils.py