input: Write a function to perform a linear search on a given array and return the position of the search item if found, otherwise return -1. The function should be able to handle arrays of strings.
  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('bookstore')==2
  assert linearSearch('mall')==3
  assert linearSearch('theatre')==4
  assert linearSearch('zoo')==-1
output: def linearSearch(array, search_item):
      for i in range(len(array)):
          if array[i] == search_item:
              return i
      return -1