public void addTargetRequests(Iterable<String> requests, long priority) {
    	if(requests == null) {
    		return;
    	}
    	
        for (String req : requests) {
        	addRequestIfValid(req, priority);
        }
    }
add urls to fetch

@param requests requests
@param priority priority
webmagic-core/src/main/java/us/codecraft/webmagic/Page.java