How to use the wikiextractor.WikiExtractor.extract function in wikiextractor

def extract(self, wiki_document):
        annotations = []
        
        #Extract the article using the general WikiExtractor:
        wiki_document = wikiextractor.WikiExtractor.extract(self, wiki_document)
        if not wiki_document: return None
        
        #This int is used to keep track of the difference between the original article with <a href="..">
        #links and the new article that only contains the label of the link.
        deltaStringLength = 0
        
        #As a first step, find all links in the article, save their positions into the annotations object
        ms = re.finditer('</a><a href="([^">([^&gt;]+)</a>', wiki_document.text)
        
        for m in ms:              
            if urllib.quote("#") not in m.group(1) or keep_anchors:
                annotations.append({
                    "uri"    :   m.group(1), 
                    "surface_form" :   m.group(2), 
                    "offset"  :   m.start() - deltaStringLength
                })

def extract(self, wiki_document):
        annotations = []
        
        #Extract the article using the general WikiExtractor:
        wiki_document = wikiextractor.WikiExtractor.extract(self, wiki_document)
        if not wiki_document: return None
        
        #This int is used to keep track of the difference between the original article with <a href="..">
        #links and the new article that only contains the label of the link.
        deltaStringLength = 0
        
        #As a first step, find all links in the article, save their positions into the annotations object
        ms = re.finditer('</a><a href="([^">([^&gt;]+)</a>', wiki_document.text)
        
        for m in ms:              
            if urllib.quote("#") not in m.group(1) or keep_anchors:
                annotations.append({
                    "u"    :   m.group(1), 
                    "s" :   m.group(2), 
                    "o"  :   m.start() - deltaStringLength
                })