def sizeof(self, fields):
        """Retrieve the size in bytes of the given fields.

        Args::

          fields   sequence of field names to query

        Returns::

          total size of the fields in bytes

        C library equivalent : VSsizeof
                                                   """

        if type(fields) in [tuple, list]:
            str = ','.join(fields)
        else:
            str = fields
        n = _C.VSsizeof(self._id, str)
        _checkErr('sizeof', n, "cannot retrieve field sizes")
        return n