text: """   Design an in-memory file system to simulate the following functions:
     
     ls: Given a path in string format. If it is a file path, return a list that
     only contains this file's name. If it is a directory path, return the list of
     file and directory names in this directory. Your output (file and directory
     names together) should in lexicographic order.
     
     mkdir: Given a directory path that does not exist, you should make a new
     directory according to the path. If the middle directories in the path don't
     exist either, you should create them as well. This function has void return
     type.
     
     addContentToFile: Given a file path and file content in string format. If the
     file doesn't exist, you need to create that file containing given content. If
     the file already exists, you need to append given content to original
     content. This function has void return type.
     
     readContentFromFile: Given a file path, return its content in string format.
     
     
     
     Example:
     
     Input:
     ["FileSystem","ls","mkdir","addContentToFile","ls","readContentFromFile"]
     [[],["/"],["/a/b/c"],["/a/b/c/d","hello"],["/"],["/a/b/c/d"]]
     
     Output: [null,[],null,null,["a"],"hello"]
     
     
  """
  
  class Solution588:
      pass
  