code: def close(self, file_des):
          
          file_handle = self.filesystem.get_open_file(file_des)
          file_handle.close()
docs: Close a file descriptor.
  
          Args:
              file_des: An integer file descriptor for the file object requested.
  
          Raises:
              OSError: bad file descriptor.
              TypeError: if file descriptor is not an integer.