input: def linearSearch(arr, value):
      """
      A linear search algorithm that takes in 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.
      >>> linearSearch([5, 3, 7, 2], 7)
      2
      >>> linearSearch([5, 3, 7, 2], 8)
      -1
      """
      for i in range(len(arr)):
          if arr[i] == value:
              return i  # value found, return index
      return -1  # value not found
output:     for i in range(len(arr)):
          if arr[i] == value:
              return i  # value found, return index
      return -1  # value not found