'Render the table header
@param table: the TABLE instance'

def html_render_table_header(self, table):

    data = self.data
    columns = data.get('c')
    labels = data.get('l')
    header_row = TR(_class='gi-column-headers')
    if columns:
        for column in columns:
            label = labels.get(column, column)
            header_row.append(TH(label))
    table.append(THEAD(header_row))
