human
Solve the following python programming problem given the following code:
def DocbookEpub(env, target, source = None, * args, **kw) : 
    '
    A pseudo-Builder, providing a Docbook toolchain for ePub output.
    ' 
    import zipfile 
    import shutil 
    def build_open_container(target, source, env) : 
        'Generate the *.epub file from intermediate outputs

        Constructs the epub file according to the Open Container Format. This
        function could be replaced by a call to the SCons Zip builder if support
        was added for different compression formats for separate source nodes.
        ' 
        zf = zipfile.ZipFile (str (target [0]), 'w') 
        mime_file = open ('mimetype', 'w') 
        mime_file.write ('application/epub+zip') 
        mime_file.close () 
        zf.write (mime_file.name, compress_type = zipfile.ZIP_STORED) 
        for s in source : 
            if os.path.isfile (str (s)) : 
                (head, tail) = os.path.split (str (s)) 
                if (not head) : 
                    continue 
s = head 
for (dirpath, dirnames, filenames) in os.walk (str (s)) : 
                for fname in filenames : 
                    path = os.path.join (dirpath, fname) 
                    if os.path.isfile (path) : 
                        zf.write (path, os.path.relpath (path, str (env.get ('ZIPROOT', ''))), zipfile.ZIP_DEFLATED) 
zf.close () 
def add_resources(target, source, env) : 
        'Add missing resources to the OEBPS directory

        Ensure all the resources in the manifest are present in the OEBPS directory.
        ' 
        hrefs = [] 
        content_file = os.path.join (source [0].abspath, 'content.opf') 
        if (not os.path.isfile (content_file)) : 
            return 
hrefs = [] 
        if has_libxml2 : 
            nsmap = { 
                'opf' : 'http://www.idpf.org/2007/opf', 
} 
            doc = libxml2.readFile (content_file, None, 0) 
            opf = doc.getRootElement () 
            xpath_context = doc.xpathNewContext () 
            for (key, val) in nsmap.iteritems () : 
               ...

    
    

    Fix the buggy line: result.extend ((mimetype + [cxml]))
assistant
#Here is Python code to fix the buggy line: result.

result.extend ((tocncx + [cxml]))