input: Write a function to implement a linear search algorithm that takes an array and a value to search for, and returns the index of the value if it is found, or -1 if it is not found. If the array is empty, return -1.
  def linearSearch(arr, value):
    for i in range(len(arr)):
      if arr[i] == value:
        return i
    return -1
  assert linearSearch([], 5) == -1
  assert linearSearch([5, 3, 7, 2], 7) == 2
  assert linearSearch([5, 3, 7, 2], 8) == -1
  assert linearSearch([1, 2, 3, 4, 5], 1) == 0
  assert linearSearch([1, 2, 3, 4, 5], 5) == 4
  assert linearSearch([1, 2, 3, 4, 5], 6) == -1
output: def linearSearch(arr, value):
    for i in range(len(arr)):
      if arr[i] == value:
        return i
    return -1