human
Solve the following python programming problem given the following code:
def _materialize(self, generation_result) : 
    remote = self.get_options ().remote 
    existing_go_buildfiles = set () 
    def gather_go_buildfiles(rel_path) : 
        address_mapper = self.context.address_mapper 
        for build_file in address_mapper.scan_build_files (base_path = rel_path) : 
            existing_go_buildfiles.add (build_file.relpath) 
gather_go_buildfiles (generation_result.local_root) 
    if (remote and (generation_result.remote_root != generation_result.local_root)) : 
        gather_go_buildfiles (generation_result.remote_root) 
targets = set (self.context.build_graph.targets (self.is_go)) 
    if (remote and generation_result.remote_root) : 
        remote_root = os.path.join (get_buildroot (), generation_result.remote_root) 
        targets.update (self.context.scan (remote_root).targets (self.is_remote_lib)) 
failed_results = [] 
    for result in self.generate_build_files (targets) : 
        existing_go_buildfiles.discard (result.build_file_path) 
        result.log (self.context.log) 
        if result.failed : 
            failed_results.append (result) 
if existing_go_buildfiles : 
        deleted = [] 
        for existing_go_buildfile in existing_go_buildfiles : 
            spec_path = os.path.dirname (result) 
            for address in self.context.address_mapper.addresses_in_spec_path (spec_path) : 
                target = self.context.address_mapper.resolve (address) 
                if isinstance (target, GoLocalSource) : 
                    os.unlink (existing_go_buildfile) 
                    deleted.append (existing_go_buildfile) 
if deleted : 
            self.context.log.info ('Deleted the following obsolete BUILD files:
\t{}'.format ('
\t'.join (sorted (deleted)))) 
if failed_results : 
        self.context.log.error ('Un-pinned (FLOATING) Go remote library dependencies are not allowed in this repository!
Found the following FLOATING Go remote libraries:
\t{}'.format ('
\t'.join (('{}'.format (result) for result in failed_results)))) 
       ...

    
    

    Fix the buggy line: spec_path = os.path.dirname (result)
assistant
#Here is Python code to fix the buggy line: spec_path = os.

spec_path = os.path.dirname (existing_go_buildfile)