input: 
  import numpy as np
  
  def runningTotal(arr):
      """
      Using NumPy, this function returns an array with the running total of numbers in the given input array.
      
      >>> runningTotal([1, 2, 3, 4])
      array([ 1,  3,  6, 10])
      
      >>> runningTotal([5, 5, 5, 5])
      array([ 5, 10, 15, 20])
      
      >>> runningTotal([0, 0, 0, 1])
      array([0, 0, 0, 1])
      """
      return np.cumsum(arr)
  
output:     return np.cumsum(arr)