input: from typing import List
  
  def linearSearch(search_item: str, array: List[str]) -> int:
      """ Perform a linear search on a given array of strings.
      >>> linearSearch('bookstore', ['school', 'hospital', 'bookstore', 'mall', 'theatre'])
      2
      >>> linearSearch('museum', ['school', 'hospital', 'bookstore', 'mall', 'theatre'])
      -1
      """
      for i in range(len(array)):
          if array[i] == search_item:
              return i
      return -1
output:     for i in range(len(array)):
          if array[i] == search_item:
              return i
      return -1