input: def linearSearch(arr: List[int], value: int) -> int:
      """
      Implements a linear search algorithm to find the index of a given value in an array.
      Returns the index if the value is found, otherwise returns -1.
      
      >>> linearSearch([5, 3, 7, 2], 7)
      2
      >>> linearSearch([5, 3, 7, 2], 8)
      -1
      """
output:     for i in range(len(arr)):
          if arr[i] == value:
              return i
      return -1