Get the length of a sorted set in Redis

    CLI Example:

    .. code-block:: bash

        salt '*' redis.zcard foo_sorted

def zcard(key, host=None, port=None, db=None, password=None):
    '''
    Get the length of a sorted set in Redis

    CLI Example:

    .. code-block:: bash

        salt '*' redis.zcard foo_sorted
    '''
    server = _connect(host, port, db, password)
    return server.zcard(key)