def siblings_files(path):
    """Return a list of sibling files available."""
    file_basename, extension = splitext(path)
    main_extension = extension.lower()
    files = {}
    if extension.lower() in list(extension_siblings.keys()):
        for text_extension in list(extension_siblings[main_extension].keys()):
            if isfile(file_basename + text_extension):
                files[file_basename + text_extension] = (
                    extension_siblings[main_extension][text_extension])

    if len(files) > 0:
        mime_base_file = extension_siblings[main_extension][main_extension]
    else:
        mime_base_file = None
    return files, mime_base_file
Return a list of sibling files available.