All the following are sources of revenue of a political party except

Political parties typically generate revenue from various sources, including payment of dues, donations, and fund raising. However, custom duties are not a source of revenue for political parties. Custom duties are taxes imposed on imported goods and are collected by the government, not political parties. While political parties may support or oppose certain trade policies that affect custom duties, they do not directly benefit from or receive revenue from custom duties. Payment of dues, donations, and fund raising, on the other hand, are all common sources of revenue for political parties. Payment of dues typically comes from party members, while donations and fund raising involve soliciting money from individuals, corporations, or other organizations that support the party's goals and agenda.