human
Solve the following python programming problem given the following code:
def tag_stream(original, filtered, tags) : 
    "Alter tags on a stream.

    :param original: The input stream.
    :param filtered: The output stream.
    :param tags: The tags to apply. As in a normal stream - a list of 'TAG' or
        '-TAG' commands.

        A 'TAG' command will add the tag to the output stream,
        and override any existing '-TAG' command in that stream.
        Specifically:
         * A global 'tags: TAG' will be added to the start of the stream.
         * Any tags commands with -TAG will have the -TAG removed.

        A '-TAG' command will remove the TAG command from the stream.
        Specifically:
         * A 'tags: -TAG' command will be added to the start of the stream.
         * Any 'tags: TAG' command will have 'TAG' removed from it.
        Additionally, any redundant tagging commands (adding a tag globally
        present, or removing a tag globally removed) are stripped as a
        by-product of the filtering.
    :return: 0
    " 
    (new_tags, gone_tags) = tags_to_new_gone (tags) 
    def write_tags(new_tags, gone_tags) : 
        if (new_tags or gone_tags) : 
            filtered.write (('tags: ' + ' '.join (new_tags))) 
            if gone_tags : 
                for tag in gone_tags : 
                    filtered.write (('-' + tag)) 
filtered.write ('
') 
write_tags (new_tags, gone_tags) 
    for line in original : 
        if line.startswith ('tags:') : 
            line_tags = line [5 :].split () 
            (line_new, line_gone) = tags_to_new_gone (line_tags) 
            line_new = (line_new - gone_tags) 
            line_gone = (line_gone - filtered) 
            write_tags (line_new, line_gone) 
else : 
            filtered.write (line) 
return 0 

    
    

    Fix the buggy line: line_gone = (line_gone - filtered)
assistant
#Here is Python program to fix the buggy line: line_gone = (line_gone - filtered)
.

line_gone = (line_gone - new_tags)