PML(N) quaid and former prime minister Mian Nawaz Sharif has said Peoples Party and other political parties are national assets. Addressing a press conference at Sindh Chief Minister House along with Chief Minister Sindh Qaim Ali Shah, Nawaz said PPP is an important political force and it should persist in the political system. Nawaz urged for positive criticism against each other and called all political forces to join hands to seek solutions of the national problems.