code: def embeddedFileAdd(self, buffer, name, filename=None, ufilename=None, desc=None):
          
  
          if self.isClosed or self.isEncrypted:
              raise ValueError("operation illegal for closed / encrypted doc")
  
  
          return _fitz.Document_embeddedFileAdd(self, buffer, name, filename, ufilename, desc)
docs: Embed a new file.