Sets the column count and list of columns to the inputed column list.
        
        :param      columns | [<str>, ..]

def setColumns(self, columns):
        """
        Sets the column count and list of columns to the inputed column list.
        
        :param      columns | [<str>, ..]
        """
        self.setColumnCount(len(columns))
        self.setHeaderLabels(columns)