code: def bs_se(bs_pdf):
      """Calculate the bootstrap standard error estimate of a statistic."""
      N = len(bs_pdf)
      return np.std(bs_pdf) * np.sqrt(N / (N - 1))
  
file_path: dipy/dipy/boots/resampling.py
imports: import numpy
  import scipy
  import warnings
label_desc: Use image node_id 1 for calling a global function with example usage: bs_se(bs_pdf) and returns: unknown