Checks if a role exists.

    CLI Example:

    .. code-block:: bash

        salt minion mssql.role_exists db_owner

def role_exists(role, **kwargs):

    '''
    Checks if a role exists.

    CLI Example:

    .. code-block:: bash

        salt minion mssql.role_exists db_owner
    '''
    # We should get one, and only one row
    return len(tsql_query(query='sp_helprole "{0}"'.format(role), as_dict=True, **kwargs)) == 1