input: Write a function to perform a linear search on a given array and return the position of the item if found, otherwise return -1. Use the given array: ['school', 'hospital', 'bookstore', 'mall', 'theatre'].
  
  def linearSearch(search_item):
      array = ['school', 'hospital', 'bookstore', 'mall', 'theatre']
      for i in range(len(array)):
          if array[i] == search_item:
              return i
      return -1
  
  assert linearSearch('school')==0
  assert linearSearch('mall')==3
  assert linearSearch('library')==-1
output: def linearSearch(search_item):
      array = ['school', 'hospital', 'bookstore', 'mall', 'theatre']
      for i in range(len(array)):
          if array[i] == search_item:
              return i
      return -1