input: 
  import numpy as np
  
  def runningTotal(arr: np.ndarray) -> np.ndarray:
      """ Returns an array with the running total of numbers in a given list.
      >>> runningTotal(np.array([1, 2, 3, 4]))
      np.array([1, 3, 6, 10])
      >>> runningTotal(np.array([0, 0, 0, 0]))
      np.array([0, 0, 0, 0])
      """
      return np.cumsum(arr)
  
output:     return np.cumsum(arr)