def METHOD_NAME(s):
    """Normalize a pathname.  Will return the same result for
    equivalent paths."""
    if ":" not in s:
        return ":"+s
    comps = s.split(":")
    i = 1
    while i < len(comps)-1:
        if comps[i] == "" and comps[i-1] != "":
            if i > 1:
                del comps[i-1:i+1]
                i = i - 1
            else:
                # best way to handle this is to raise an exception
                raise norm_error, 'Cannot use :: immediately after volume name'
        else:
            i = i + 1
    s = ":".join(comps)
    # remove trailing ":" except for ":" and "Volume:"
    if s[-1] == ":" and len(comps) > 2 and s != ":"*len(s):
        s = s[:-1]
    return s