<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def ordered_cols(self, columns, section):
 """Return ordered list of columns, from given columns and the name of the section """

        columns = list(columns)  # might be a tuple
        fixed_cols = [self.key]
        if section.lower() == "different":
            fixed_cols.extend([Differ.CHANGED_MATCH_KEY, Differ.CHANGED_OLD, Differ.CHANGED_NEW])
        map(columns.remove, fixed_cols)
        columns.sort()
        return fixed_cols + columns