code: def ECDF(values):
      """
      Return the ECDF of an array as a step function.
      """
      x = np.array(values, copy=True)
      x.sort()
      x.shape = np.prod(x.shape, axis=0)
      n = x.shape[0]
      y = (np.arange(n) + 1.0) / n
      return StepFunction(x, y)
  
file_path: nipy/nipy/algorithms/statistics/models/utils.py
imports: import numpy
  import scipy.interpolate
label_desc: Use image node_id 2 for calling a global function with example usage: ECDF(values) and returns: StepFunction