Sets the identifier for the term
        @type i: string
        @param i: lemma identifier

def set_id(self,i):
        """
        Sets the identifier for the term
        @type i: string
        @param i: lemma identifier
        """
        if self.type == 'NAF':
            self.node.set('id',i)
        elif self.type == 'KAF':
            self.node.set('mid',i)