def navbarItems(activePage):
    pages = ["Students", "Assistants", "Experiments", "Appointments", "Groups", "Users"]
    items = ""
    for page in pages:
        active = ""
        lowerPage = page.lower().replace(" ", "_")
        if lowerPage == activePage:
            active = " active"
        items += '<a class="nav-link' + active + '" href="' + lowerPage + '">' + page + '</a>'
    return items

def td(cell):
    return "<td>" + str(cell) + "</td>"

def th(cell):
    return '<th data-sortable="true">' + str(cell) + '</th>'