def standardize_fs_data(fs_data, subject_ID_col):
    """ Takes df from FS output and stadardizes column names for both left and right hemi
    """
    fs_useful_cols = [subject_ID_col] #'SubjID'
    fs_col_renames = {}
    for roi in fs_data.columns:
        prefix = None
        name_split = roi.split('_')
        if name_split[0] in ['L','R']:
            roi_rename = name_split[0] + '_' + name_split[1]
            fs_useful_cols.append(roi_rename)
            fs_col_renames[roi] = roi_rename
            
    fs_data_std = fs_data.rename(columns=fs_col_renames).copy()

    # Splitting SubjID column to ignore site name
    _, fs_data_std[subject_ID_col] = fs_data_std[subject_ID_col].str.rsplit('_', 1).str
    return fs_data_std