def read_group_list_text_file(group_list_text_file):
    """Read in the group-level analysis participant-session list text file."""

    with open(group_list_text_file, "r") as f:
        group_list = f.readlines()

    # each item here includes both participant and session, and this also will
    # become the main ID column in the written design matrix CSV
    group_list = [str(x).rstrip("\n") for x in group_list if x != ""]

    return group_list