def datetime(value, format_str='%Y/%m/%d %H:%M'):
    """
    Convert a datetime to a different format.

    The default format looks like --> 2016/11/25 12:34

    Args:
        value (datetime.datetime): input date and time
        format_str (str): The datetime format string to apply to value

    Returns:
        str: value, after the format_str has been applied
    """
    return value.strftime(format_str)
