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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 db_exists(name, user=None, password=None, host=None, port=None, authdb=None):
    '''
    Checks if a database exists in MongoDB

    CLI Example:

    .. code-block:: bash

        salt '*' mongodb.db_exists <name> <user> <password> <host> <port>
    '''
    dbs = db_list(user, password, host, port, authdb=authdb)

    if isinstance(dbs, six.string_types):
        return False

    return name in dbs