input: Write a function to create a search engine in Python that performs a linear search through a given array. The function should take a search item as input and return the position of the item in the array if found, or -1 if not found.
  assert linearSearch('bookstore')==2
  assert linearSearch('hospital')==1
  assert linearSearch('mall')==3
  assert linearSearch('park')==-1
  assert linearSearch('school')==0
output: def linearSearch(item):
      array = ['school', 'hospital', 'bookstore', 'mall']
      for i in range(len(array)):
          if array[i] == item:
              return i
      return -1