def to_boolean(bool_):
    """
    Convert to boolean from String

    Return: a boolean value

    If the string is not a representation of a boolean value, the method returns False.
    """
    if bool_ is None:
        return False
    if bool_ is True or bool_ is False:
        return bool_
    else:
        return bool_[0].upper() == 'T' or bool_[0].upper() == 'Y'
