Root element must be <sonnet>. Valid values for the type attribute are "Shakespearean" or "Petrarchan." The <sonnet> element contains a <author> element, an optional <title> element, and a <lines< element. The first child of the <sonnet> element must be an <author> element. If you use the optional <title> element, the <sonnet> element must contain the <author>, <title> and <lines> elements in that order. An <author> element must have the elements <lastName>, <firstName>, <nationality> <yearOfBirth> and <yearOfDeath>. (The <yearOfBirth> and <yearOfDeath> elements are optional. The first child of the <author> element must be a <lastName> element. The second child of the <author> element must be a <firstName> element. The third child of the <author> element must be a <nationality> element. The fourth child of the <author> element must be a <yearOfBirth> element. A sonnet must have 14 <line>s. The <lines> element can only contain <line> elements.