def METHOD_NAME(s):
    """Normalize a pathname.  Will return the same result for
    equivalent paths."""
    colon = _get_colon(s)
    if colon not in s:
        return colon + s
    comps = s.split(colon)
    i = 1
    while i < len(comps)-1:
        if not 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 = colon.join(comps)
    # remove trailing ":" except for ":" and "Volume:"
    if s[-1:] == colon and len(comps) > 2 and s != colon*len(s):
        s = s[:-1]
    return s