func (g *Grammar) SymbolIsNullable(sym_id SymbolID) int {
	return int(C.marpa_g_symbol_is_nullable(g.handle, C.Marpa_Symbol_ID(sym_id)))
}
func (g Grammar) SymbolIsNullable(sym_id SymbolID) int {
	return int(C.marpa_g_symbol_is_nullable(g.grammar, sym_id.id))
}