code: def _getPageInfo(self, pno, what):
          
          if self.isClosed or self.isEncrypted:
              raise ValueError("operation illegal for closed / encrypted doc")
  
          val = _fitz.Document__getPageInfo(self, pno, what)
  
          x = []
          for v in val:
              if v not in x:
                  x.append(v)
          val = x
  
          return val
docs: Show fonts or images used on a page.