human
Solve the following python programming problem given the following code:
def LookupSources(env, variant_dir, src_dir, duplicate = True, src_filter = None) : 
    SRC_FILTER_PATTERNS_RE = re.compile ('(\\+|\\-)<([^>]+)>') 
    def _append_build_item(items, item, src_dir) : 
        if env.IsFileWithExt (item, (SRC_BUILD_EXT + SRC_HEADER_EXT)) : 
            items.add (item.replace ((src_dir + sep), '')) 
def _match_sources(src_dir, src_filter) : 
        matches = set () 
        src_filter = src_filter.replace ('/', sep).replace ('\\', sep) 
        for (action, pattern) in SRC_FILTER_PATTERNS_RE.findall (src_filter) : 
            items = set () 
            for item in glob (join (src_dir, pattern)) : 
                if isdir (item) : 
                    for (root, _, files) in walk (item, followlinks = True) : 
                        for f in files : 
                            _append_build_item (items, join (root, f), src_dir) 
else : 
                    _append_build_item (items, item, src_dir) 
if (action == '+') : 
                matches |= items 
else : 
                matches -= items 
return sorted (list (matches)) 
sources = [] 
    variants = [] 
    src_dir = env.subst (src_dir) 
    if src_dir.endswith (sep) : 
        src_dir = src_dir [: (- 1)] 
for item in _match_sources (src_dir, (src_filter or SRC_DEFAULT_FILTER)) : 
        _reldir = dirname (item) 
        _src_dir = (join (src_dir, _reldir) if _reldir else src_dir) 
        _var_dir = (join (variant_dir, _reldir) if _reldir else variant_dir) 
        if (_var_dir not in variants) : 
            variants.append (_var_dir) 
            env.VariantDirWrap (_var_dir, _src_dir, sources) 
if env.IsFileWithExt (item, SRC_BUILD_EXT) : 
            sources.append (env.File (join (_var_dir, basename (item)))) 
return sources 

    
    

    Fix the buggy line: env.VariantDirWrap (_var_dir, _src_dir, sources)
assistant
#Here is Python program to fix the buggy line: env.

env.VariantDirWrap (_var_dir, _src_dir, duplicate)