input: Write a function to implement the Insertion Sort algorithm in Python and sort the given array in non-decreasing order. If the input array is empty, return an empty array.
  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, -1, 2, 9, 5, 3])==[-1, 2, 3, 5, 5, 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