code: def sensitivity_index(a, alpha=None):
      a = np.array(a)
      return np.divide(
          _partial_first_order_variance(a, alpha),
          _total_variance(a, alpha),
      )
  
imports: import numpy
label_desc: Use image node_id 4 for calling a global function with example usage: sensitivity_index(a, alpha) and returns: np