<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def namedb_get_all_namespace_ids( cur ):
 """ Get a list of all READY namespace IDs. """


    query = "SELECT namespace_id FROM namespaces WHERE op = ?;"
    args = (NAMESPACE_READY,)

    namespace_rows = namedb_query_execute( cur, query, args )
    ret = []
    for namespace_row in namespace_rows:
        ret.append( namespace_row['namespace_id'] )

    return ret