def bool_env(value: bool):
    """
    Takes a boolean value(or None) and return the serialized version to be used as an environment variable

    Examples:
        >>> bool_env(True)
        "true"

        >>> bool_env(False)
        "false"

        >>> bool_env(None)
        "false"
    """

    if value is True:
        return "true"
    else:
        return "false"