code: def siblings_files(path):
      
      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
docs: Return a list of sibling files available.