def build_member_matrix(mbr_list):
    """Return a matrix of information on the given members list."""
    headers = [
        'Last Name',            # Member.last_name
        'First Name',           # Member.first_name
        'Party',                # Member.party
    ]
    matrix = [headers,]
    for mbr in mbr_list:
        row = [
            mbr.last_name,
            mbr.first_name,
            mbr.party,
        ]
        matrix.append(row)
    return matrix