def urlCat(*urls):
    """
        Concatenate a series of URLs correctly.
    """
    out = []
    for i, s in enumerate(urls):
        if s:
            if i == 0:
                out.append(s.rstrip("/"))
            elif i == len(urls)-1:
                out.append(s.lstrip("/"))
            else:
                out.append(s.strip("/"))
    return "/".join(out)