input: import numpy as np
  
  def runningTotal(arr):
      """ Given a list of numbers, return an array with the running total of numbers in the list.
      >>> runningTotal([1, 2, 3, 4])
      array([1, 3, 6, 10])
      >>> runningTotal([5, 10, 15, 20])
      array([5, 15, 30, 50])
      """
      return np.cumsum(arr)
output:     return np.cumsum(arr)