input: Write a function to generate an array that contains the running total of numbers in a given list using numpy. 
  
  assert runningTotal([1, 2, 3, 4])==[1, 3, 6, 10]
  assert runningTotal([10, 20, 30])==[10, 30, 60]
  assert runningTotal([5])==[5]
  assert runningTotal([])==[]
  assert runningTotal([-1, -2, -3])==[-1, -3, -6]
output: import numpy as np
  
  def runningTotal(numbers):
      if not numbers:
          return []
      arr = np.array(numbers)
      return np.cumsum(arr).tolist()