old_contents: import os
  
  def ensure_path(path):
      '''
      This function checks if a path to a directory exists. If the path exists, this 
      function does nothing but return the given path. If the path does not exist, 
      then it makes all of the necessary directories for the path to exist.
  
      ARGUMENTS:
          path - String of a path to a directory.
      RETURNS:
          path - String, the same path given. Now, the directory at the given path
                 exists, if it didn't already.
      ex.)
          my_path = ensure_path("I/need/this/path")
          # Now my_path exists.
          assert my_path == "I/need/this/path"
          assert os.path.exists(my_path)
      '''
  
      #Do nothing if the path already exists.
      if os.path.exists(path):
          return path
  
      #Precondition path
      if path[-1] != "/":
          path += "/"
  
      #Go through each subdirectory and create it if it doesn't exist.
      direcs = [path[:i+1] for i,c in enumerate(path) if c=="/"]
      for direc in direcs:
          if not os.path.exists(direc):
              os.makedirs(direc)
      return path
  
new_contents: import os
  
  def ensure_path(path):
      '''
      This function checks if a path to a directory exists. If the path exists, this 
      function does nothing but return the given path. If the path does not exist, 
      then it makes all of the necessary directories for the path to exist.
  
      ARGUMENTS:
          path - String of a path to a directory.
      RETURNS:
          path - String, the same path given. Now, the directory at the given path
                 exists, if it didn't already.
      ex.)
          my_path = ensure_path("I/need/this/path")
          # Now the directory I/need/this/path exists.
          assert my_path == "I/need/this/path"
          assert os.path.exists(my_path)
      '''
  
      #Do nothing if the path already exists.
      if os.path.exists(path):
          return path
  
      #Precondition path
      if path[-1] != "/":
          path += "/"
  
      #Go through each subdirectory and create it if it doesn't exist.
      direcs = [path[:i+1] for i,c in enumerate(path) if c=="/"]
      for direc in direcs:
          if not os.path.exists(direc):
              os.makedirs(direc)
      return path
  
subject: Update ensure_path.py