input: from typing import List
  
  
  def linear_search(arr: List[int], x: int) -> int:
      """
      Perform a linear search for the element 'x' in the list 'arr'.
  
      >>> linear_search([1, 2, 3, 4, 5], 3)
      2
      >>> linear_search([1, 2, 3, 4, 5], 6)
      -1
      """
      for index, item in enumerate(arr):
          if item == x:
              return index
      return -1
output:     for index, item in enumerate(arr):
          if item == x:
              return index
      return -1