'This method is meant to be overriden by the subclasses of
SearchEngine.py
This method searches the web and returns a list of URLs.
:param query: The query that we want to perform in the search engine
:param start: The first result item
:param count: How many results to get from start'

def search(self, query, start, count=10):

    raise NotImplementedError('SearchEngine    subclasses    should    implement    the    search    method.')
