The legislature is a branch of the running of a nation with the power over legislation. The enacting and alteration of laws is the main duty of a legislature, but it may also be required to perform other tasks such as the election of the Head of State, executive or government. Legislatures are usually unicameral (consisting of one parliamentary house) or bicameral (consisting of two parliamentary houses), however on occasion they are tricameral (consisting of three parliamentary houses), as in Colearine.