(g) The “members of the service staff” are the members of the staff of the mission in the domestic service of the mission; (h) A “private servant” is a person who is in the domestic service of a member of the mission and who is not an employee of the sending State; (i) The “premises of the mission” are the buildings or parts of buildings and the land ancillary thereto, irrespective of ownership, used for the purposes of the mission including the residence of the head of the mission. Article 2 The establishment of diplomatic relations between States, and of permanent diplomatic missions, takes place by mutual consent. Article 3 1. The functions of a diplomatic mission consist, inter alia, in: (a) Representing the sending State in the receiving State; (b) Protecting in the receiving State the interests of the sending State and of its nationals, within the limits permitted by international law; (c) Negotiating with the Government of the receiving State; (d) Ascertaining by all lawful means conditions and developments in the receiving State, and reporting thereon to the Government of the sending State; (e) Promoting friendly relations between the sending State and the receiving State, and developing their economic, cultural and scientific relations. 2. Nothing in the present Convention shall be construed as preventing the performance of consular functions by a diplomatic mission. Article 4 1. The sending State must make certain that the agrément of the receiving State has been given for the person it proposes to accredit as head of the mission to that State. 2. The receiving State is not obliged to give reasons to the sending State for a refusal of agrément. 3