@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof SpanList spanList)) return false;
        if (!super.equals(o)) return false;

        if (children() != null ? !children().equals(spanList.children()) : spanList.children() != null) return false;

        return true;
    }
Returns the text that is covered by this SpanNode.

@param text the input text
@return the text that is covered by this SpanNode.
document/src/main/java/com/yahoo/document/annotation/SpanList.java