def METHOD_NAME(workflow, files, ifo, out_dir, tags=None):
    make_analysis_dir(out_dir)
    tags = [] if not tags else tags
    node = MergePSDFiles(workflow.cp, 'merge_psds',
                         ifos=ifo, out_dir=out_dir,
                         tags=tags).create_node()
    node.add_input_list_opt('--psd-files', files)
    node.new_output_file_opt(workflow.analysis_time, '.hdf', '--output-file')
    workflow += node
    return node.output_files[0]