input: Write a function to calculate the running total of numbers in a given list using numpy. Return an array with the running total.
  assert np.array_equal(runningTotal([1, 2, 3, 4]), [1, 3, 6, 10])
  assert np.array_equal(runningTotal([5, 10, 15]), [5, 15, 30])
  assert np.array_equal(runningTotal([]), [])
  assert np.array_equal(runningTotal([-1, -2, -3]), [-1, -3, -6])
  assert np.array_equal(runningTotal([100]), [100])
output: import numpy as np
  
  def runningTotal(numbers):
      return np.cumsum(numbers)