input: Write a function to generate an array with the running total of numbers in a given list using numpy. The function should take a list of integers as input and return a numpy array with the cumulative sum of those integers. If the input list is empty, the function should return an empty numpy array.
  
  import numpy as np
  
  def runningTotal(arr):
      return np.cumsum(arr)
  
  assert np.array_equal(runningTotal([1, 2, 3, 4]), np.array([1, 3, 6, 10]))
  assert np.array_equal(runningTotal([-1, 0, 1]), np.array([-1, -1, 0]))
  assert np.array_equal(runningTotal([]), np.array([]))
  assert np.array_equal(runningTotal([10, 10, 10]), np.array([10, 20, 30]))
  assert np.array_equal(runningTotal([5, -5, 5]), np.array([5, 0, 5]))
output: import numpy as np
  
  def runningTotal(arr):
      return np.cumsum(arr)