def unique(sorted_list):
    """Return a new list containing all unique elements in their original order

    Keyword arguments:
    sorted_list -- a list of comparable elements in which all duplicates are
                   next to one another
    """
    res = []
    last = None
    for element in sorted_list:
        if last != element:
            # Add it to the result list
            res.append(element)
            # Skip all following instances of this element
            last = element

    return res