Scraping reliability score

[georgerichardson]

Write a function in article.Article that calculates the percentage of scraped fields which are returned empty.

We may consider expanding the definition of scraping reliability later, so suggestions welcome.

[ghost]

We can exploit '''vars()''' for this end:

## loop through each self variable in article class and test they're not 0, False, or None

def reliability(article):
	return (len([v for v in vars(article).values() if(v)])/
		    len(vars(article)))