code: def size(self):
          
          old = self.__file.tell()        # old position
  
          self.__file.seek(0, 2)          # end of file
          n_bytes = self.__file.tell()    # file size in bytes
  
          self.__file.seek(old)           # back to old position
  
          return n_bytes
docs: Calculate and return the file size in bytes.