code: def has_item(self, url):
          
  
          _hash = self.build_hash(url)
          self.execute('BEGIN')
          self.execute('''
              SELECT id
              FROM cache
              WHERE id = x%s
              LIMIT 1
          ''', (_hash,))
          row = self.cursor.fetchone()
          self.execute('COMMIT')
          return True if row else False
docs: Test if required item exists in the cache.