rename the columns in the dependent peptides table from
    the raw file to the corresponding {experiment}_{fraction}.
    :param dep: dependent peptides table.
    :param exp: experimental design table.

def _set_column_names(dep, exp):
    """ rename the columns in the dependent peptides table from
    the raw file to the corresponding {experiment}_{fraction}.
    :param dep: dependent peptides table.
    :param exp: experimental design table.
    """
    colnames = exp['Experiment'].astype(str) + '_' + exp['Fraction'].astype(str)
    file2col = dict(zip(exp['Raw file'], colnames))
    _dep = dep.rename(columns=file2col)
    _dep.columns.name = 'Column Name'
    return _dep