':return: Tokens associated with the login (username and password)'

def get_login_tokens(self):

    assert self.is_login_form(), 'Login    form    is    required'
    user_token = None
    pass_token = None
    for token in self.iter_tokens():
        ptype = self.get_parameter_type(token.get_name()).lower()
        if (ptype == INPUT_TYPE_PASSWD):
            pass_token = token
        elif (ptype == INPUT_TYPE_TEXT):
            user_token = token
    return (user_token, pass_token)
