def date2str(dt, format_str=None):
    """
    Convert list of datetime objects to legible strings

    Parameters
    ----------
    dt : datetime.datetime
        Single or list of datetime object(s)
    format_str : string
        Timestamp string formatting, default: '%Y-%m-%d %H:%M:%S.%f'. 
        See datetime.strftime documentation for timestamp string formatting

    Returns
    -------
    time : string
        Converted timestamps

    """
    if format_str is None:
        format_str = '%Y-%m-%d %H:%M:%S.%f'

    if not isinstance(dt, list):
        dt = [dt]

    return [t.strftime(format_str) for t in dt]