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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def count_cookies(self, domain):
        '''Return the number of cookies for the given domain.'''
        cookies = self.cookie_jar._cookies

        if domain in cookies:
            return sum(
                [len(cookie) for cookie in cookies[domain].values()]
            )
        else:
            return 0