input: Write a function to perform the Insertion Sort algorithm on a list of numbers in Python and return the sorted list. If the input list is empty, 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
  
  if __name__ == '__main__':
      assert insertionSort([3, 1, 5, 2, 4])==[1, 2, 3, 4, 5]
      assert insertionSort([10, 9, 8, 7, 6])==[6, 7, 8, 9, 10]
      assert insertionSort([])==[]
      assert insertionSort([1])==[1]
      assert insertionSort([4, 3, 2, 1])==[1, 2, 3, 4]
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