def fetch(self):
        content = self.buffer
        self.buffer = ''

        return content
get size of longest value in specific column
dataset/ETHPy150Open sdispater/cleo/cleo/outputs/buffered_output.py/BufferedOutput.fetch--crossover with--dataset/ETHPy150Open projectatomic/osbs-client/osbs/cli/render.py/TableFormatter._longest_val_in_column