def nth(lst, n):
    """Return the nth item in the list."""
    expect_type(n, (String, Number), unit=None)

    if isinstance(n, String):
        if n.value.lower() == 'first':
            i = 0
        elif n.value.lower() == 'last':
            i = -1
        else:
            raise ValueError("Invalid index %r" % (n,))
    else:
        # DEVIATION: nth treats lists as circular lists
        i = n.to_python_index(len(lst), circular=True)

    return lst[i]
Return the nth item in the list.