input: Write a function to sort a list of numbers using the Insertion Sort algorithm in Python. The function should accept a list of integers as input and return the sorted list. If the input list is empty, the function should return an empty list.
  
  def insertionSort(arr):
      if not arr:
          return []
      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([3, 4, 5, 1, 2]) == [1, 2, 3, 4, 5]
  assert insertionSort([3, 5, 10, 1, 2]) == [1, 2, 3, 5, 10]
  assert insertionSort([4, 3, 1, 2]) == [1, 2, 3, 4]
  assert insertionSort([3, 5, 4, 1, 2]) == [1, 2, 3, 4, 5]
  assert insertionSort([]) == []
output: def insertionSort(arr):
      if not arr:
          return []
      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