return library examples.

    EXAMPLE1,EXAMPLE2,..

def lib_examples(lib):
    """return library examples.

    EXAMPLE1,EXAMPLE2,..

    """
    d = lib_examples_dir(lib)
    if not d.exists():
        return []
    ls = d.dirs()
    ls = [x.name for x in ls]
    ls.sort()
    return ls