code: def mkdir_p(dirname):
      
      assert dirname is not None
      if dirname == '' or os.path.isdir(dirname):
          return
      try:
          os.makedirs(dirname)
      except OSError as e:
          if e.errno != errno.EEXIST:
              raise e
docs: Like "mkdir -p", make a dir recursively, but do nothing if the dir exists
  
      Args:
          dirname(str):