code: def _fdopen_ver2(self, file_des, mode='r',
                       bufsize=None):  # pylint: disable=unused-argument
          
          if not is_int_type(file_des):
              raise TypeError('an integer is required')
  
          try:
              return FakeFileOpen(self.filesystem).call(file_des, mode=mode)
          except IOError as exc:
              self.filesystem.raise_os_error(exc.errno, exc.filename)
docs: Returns an open file object connected to the file descriptor
          file_des.
  
          Args:
              file_des: An integer file descriptor for the file object requested.
              mode: Additional file flags. Currently checks to see if the mode
                  matches the mode of the requested file object.
              bufsize: ignored. (Used for signature compliance with
                  __builtin__.fdopen)
  
          Returns:
              File object corresponding to file_des.
  
          Raises:
              OSError: if bad file descriptor or incompatible mode is given.
              TypeError: if file descriptor is not an integer.