input: Write a function to return an array with the running total of numbers in a given list using numpy. The function should use `np.cumsum` and be named `runningTotal`.
  assert np.all(runningTotal([1, 2, 3, 4]) == np.array([1, 3, 6, 10]))
  assert np.all(runningTotal([2, 4, 6, 8]) == np.array([2, 6, 12, 20]))
  assert np.all(runningTotal([10, 20, 30]) == np.array([10, 30, 60]))
  assert np.all(runningTotal([5]) == np.array([5]))
  assert np.all(runningTotal([]) == np.array([]))
output: def runningTotal(lst):
      import numpy as np
      return np.cumsum(lst)