class Author:

def __init__(self, id, firstname, lastname):
    self._validateid(id, "ID")
    self._validate_author(firstname, "First Name")
    self._validate_author(lastname, "Last Name")

    self._id = id
    self._firstname = firstname
    self._lastname = lastname

def _validateid(self, id, error_message):
    if id < 1:
        raise ValueError(error_message + " is invalid")

def _validate_author(self, parameter, error_message):
    if not parameter:
        raise TypeError(error_message + " is missing")

@property
def iden(self):
    return self._id

@property
def first_name(self):
    return self._firstname

@property
def last_name(self):
    return self._lastname

def __lt__(self, other):
    if isinstance(other, Author):
        return (self.iden, self.first_name.lower(), self.last_name.lower()) < (other.iden, other.first_name.lower(), other.last_name.lower())
    return NotImplemented

def __le__(self, other):
    if isinstance(other, Author):
        return (self.iden, self.first_name.lower(), self.last_name.lower()) <= (other.iden, other.first_name.lower(), other.last_name.lower())
    return NotImplemented

def __eq__(self, other):
    if isinstance(other, Author):
        return (self.iden, self.first_name.lower(), self.last_name.lower()) == (other.iden, other.first_name.lower(), other.last_name.lower())
    return NotImplemented

def __ne__(self, other):
    if isinstance(other, Author):
        return (self.iden, self.first_name.lower(), self.last_name.lower()) != (other.iden, other.first_name.lower(), other.last_name.lower())
    return NotImplemented

def __ge__(self, other):
    if isinstance(other, Author):
        return (self.iden, self.first_name.lower(), self.last_name.lower()) >= (other.iden, other.first_name.lower(), other.last_name.lower())
    return NotImplemented

def __gt__(self, other):
    if isinstance(other, Author):
        return (self.iden, self.first_name.lower(), self.last_name.lower()) > (other.iden, other.first_name.lower(), other.last_name.lower())
    return NotImplemented

def __hash__(self):
    return hash((self.iden, self.first_name.lower(), self.last_name.lower()))