Check to see if a stack exists.

    CLI Example:

    .. code-block:: bash

        salt myminion boto_cfn.exists mystack region=us-east-1

def exists(name, region=None, key=None, keyid=None, profile=None):
    '''
    Check to see if a stack exists.

    CLI Example:

    .. code-block:: bash

        salt myminion boto_cfn.exists mystack region=us-east-1
    '''
    conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)

    try:
        # Returns an object if stack exists else an exception
        exists = conn.describe_stacks(name)
        log.debug('Stack %s exists.', name)
        return True
    except BotoServerError as e:
        log.debug('boto_cfn.exists raised an exception', exc_info=True)
        return False