def _check_bind_options(kw):
    """Check keyword options passed to dummy mailer ``.bind`` method
    for plausibility.

    Performs the same checks that :method:`Mailer.bind` does.

    """
    valid_options = 'default_sender', 'transaction_manager'
    invalid_options = set(kw.keys()).difference(valid_options)
    if invalid_options:
        raise ValueError('invalid options: %s' % ', '.join(sorted(
            invalid_options)))
