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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_local_file_list(self):
 """ Walk the local build directory and create a list of relative and absolute paths to files. """

        file_list = []
        for (dirpath, dirnames, filenames) in os.walk(self.build_dir):
            for fname in filenames:
                # relative path, to sync with the S3 key
                local_key = os.path.join(
                    os.path.relpath(dirpath, self.build_dir),
                    fname
                )
                if local_key.startswith('./'):
                    local_key = local_key[2:]
                file_list.append(local_key)
        return file_list