input: def linearSearch(arr: list, value: int) -> int:
      """
      Perform a linear search on a given array to find the index of a specified value.
      Return the index if the value is found, otherwise return -1.
      >>> linearSearch([5, 3, 7, 2], 7)
      2
      >>> linearSearch([5, 3, 7, 2], 1)
      -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