human
Complete the below
def _readfields(lines, delimiters):

    ''''readfields(lines, delimiters) -> (delim, a list of lists of fields)
    ``delimiters`` is a list of escaped characters, e.g. r\'\t\', r\'\001\', \',\'
    Choose the best delimiter from the given list of delimiters. Return that delimiter
    and the fields parsed by using that delimiter.'
    '''
 ... Can you provide a the Python code you requested?
assistant
#Here is the Python code you requested.
    def score_delim(fields_list):
        '\n                How    good    is    this    fields_list?    Score    based    on    variance    of    the    number    of    fields\n                The    score    is    always    non-negative.    The    higher    the    better.\n                '
        n_lines = len(fields_list)
        len_list = [len(fields) for fields in fields_list]
        if (not len_list):
            raise PopupException(_('Could    not    find    any    columns    to    import'))
        if (min(len_list) == 1):
            return 0
        avg_n_fields = (sum(len_list) / n_lines)
        sq_of_exp = (avg_n_fields * avg_n_fields)
        len_list_sq = [(l * l) for l in len_list]
        exp_of_sq = (sum(len_list_sq) / n_lines)
        var = (exp_of_sq - sq_of_exp)
        return ((1000.0 / (var + 1)) + avg_n_fields)
    max_score = (-1)
    res = (None, None)
    for delim in delimiters:
        delimiter = delim.decode('string_escape')
        try:
            fields_list = _get_rows(lines, delimiter)
        except:
            LOG.exception('failed    to    get    rows')
            fields_list = [line.split(delimiter) for line in lines if line]
        score = score_delim(fields_list)
        LOG.debug(("'%s'    gives    score    of    %s" % (delim, score)))
        if (score > max_score):
            max_score = score
            res = (delim, fields_list)
    return res