input: Write a function that performs a linear search on a given array to find the position of a specified item. The function should return the position of the item if found, otherwise return -1. Below is the implementation along with test cases.
  
  def linearSearch(search_item, array):
      for i in range(len(array)):
          if array[i] == search_item:
              return i
      return -1
  
  ### Test cases:
  assert linearSearch('school', ['school', 'hospital', 'bookstore', 'mall', 'theatre']) == 0
  assert linearSearch('mall', ['school', 'hospital', 'bookstore', 'mall', 'theatre']) == 3
  assert linearSearch('library', ['school', 'hospital', 'bookstore', 'mall', 'theatre']) == -1
  assert linearSearch('bookstore', ['school', 'hospital', 'bookstore', 'mall', 'theatre']) == 2
  assert linearSearch('theatre', ['school', 'hospital', 'bookstore', 'mall', 'theatre']) == 4
output: def linearSearch(search_item, array):
      for i in range(len(array)):
          if array[i] == search_item:
              return i
      return -1