def evaluate(self, filename):
		"""Runs the lemmatize function over the contents of the file, counting the proportion of unfound lemmas."""
		with open(filename, 'r') as infile:
			lines = infile.read().splitlines()

			lemma_count = 0
			token_count = 0

			for line in lines:
				line = re.sub(r'[.,!?:;0-9]', ' ', line)
				lemmas = [lemma for (_, lemma) in self.lemmatize(line, best_guess=False)]

				token_count += len(lemmas)
				lemma_count += len(lemmas) - lemmas.count([])

			return lemma_count/token_count
Runs the lemmatize function over the contents of the file, counting the proportion of unfound lemmas.