def split_global_comment(lines):
    """Split top comments into global and first glyph comment."""
    while lines and not lines[-1]:
        lines = lines[:-1]
    try:
        splitter = lines[::-1].index('')
    except ValueError:
        global_comment = lines
        lines = []
    else:
        global_comment = lines[:-splitter-1]
        lines = lines[-splitter:]
    return global_comment, lines