code: def std(df: "DataFrame", ddof=1) -> "pd.Series":
      return var(df, ddof=ddof) ** 0.5
  
file_path: FATE/python/fate/arch/dataframe/ops/_stat.py
imports: import functools
  import numpy
  import pandas
  import torch
  from .._dataframe import DataFrame
  from ..manager import DataManager
label_desc: Use image node_id 6 for calling a global function with example usage: std(df, ddof) and returns: unknown