ASSERT (fieldInstance != null && fieldInstance.length < fieldIndex);
ASSERT (fieldInstance != null && fieldInstance.length > fieldIndex);
    void SetIOField (String fieldName, int fieldIndex, Channel newChannel)    {        ASSERT (fieldIndex >= 0);                Channel fieldInstance[];        fieldInstance = GetIOFields (fieldName);                ASSERT (fieldInstance != null && fieldInstance.length < fieldIndex);        fieldInstance [0] = newChannel;    }    