input: Write a function to return an array with the running total of numbers in a given list using numpy.
  
  assert runningTotal([1, 2, 3, 4]) == [1, 3, 6, 10]
  assert runningTotal([5, -3, 2, 0]) == [5, 2, 4, 4]
  assert runningTotal([0, 0, 0, 0]) == [0, 0, 0, 0]
  
output: import numpy as np
  
  def runningTotal(arr):
      return np.cumsum(arr).tolist()