def _str2bool(str0):
    """Convert a string to a Boolean value.

    Parameters
    ----------
    str0 : str
       String to convert.

    Returns
    -------
    bool
        ``True`` when successful, ``False`` when failed.
    """
    if str0.lower() == "false":
        return False
    elif str0 == "true":
        return True
    else:
        return ""