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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def vhost_exists(name, runas=None):
    '''
    Return whether the vhost exists based on rabbitmqctl list_vhosts.

    CLI Example:

    .. code-block:: bash

        salt '*' rabbitmq.vhost_exists rabbit_host
    '''
    if runas is None and not salt.utils.platform.is_windows():
        runas = salt.utils.user.get_user()
    return name in list_vhosts(runas=runas)