input: Write a function to sort a list of numbers using the Insertion Sort algorithm in Python. The function should modify the original list to put the numbers in ascending order and return the sorted list. If the input list is empty, the function should return an empty list.
  def insertionSort(arr):
  	for i in range(1, len(arr)):
  		current = arr[i]
  		j = i-1
  		while j>=0 and arr[j]>current:
  			arr[j+1] = arr[j]
  			j-=1
  		arr[j+1] = current
  	return arr
  assert insertionSort([2, 4, 7, 3, 8, 6, 1])==[1, 2, 3, 4, 6, 7, 8]
  assert insertionSort([5, 2, 9, 1, 5, 6])==[1, 2, 5, 5, 6, 9]
  assert insertionSort([])==[]
output: def insertionSort(arr):
  	for i in range(1, len(arr)):
  		current = arr[i]
  		j = i-1
  		while j>=0 and arr[j]>current:
  			arr[j+1] = arr[j]
  			j-=1
  		arr[j+1] = current
  	return arr