code: def get_folder_subpath(path, folder_depth):
      
      if path[0] == op.sep:
          folder_depth += 1
  
      return op.sep.join(path.split(op.sep)[0:folder_depth])
docs: Returns a folder path of path with depth given by folder_dept:
  
      Parameters
      ----------
      path: str
  
      folder_depth: int > 0
  
      Returns
      -------
      A folder path
  
      Example
      -------
      >>> get_folder_subpath('/home/user/mydoc/work/notes.txt', 3)
      >>> '/home/user/mydoc'