This method is used to set the password.

        password must be a string.

def set_password(self, password = None):
        """This method is used to set the password.

        password must be a string.

        """
        
        if password is None or type(password) is not str:
            raise KPError("Need a new image number")
        else:
            self.password = password
            self.last_mod = datetime.now().replace(microsecond=0)
            return True