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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 from_gamertag(cls, gamertag):
        '''
        Instantiates an instance of ``GamerProfile`` from
        a gamertag

        :param gamertag: Gamertag to look up

        :raises: :class:`~xbox.exceptions.GamertagNotFound`

        :returns: :class:`~xbox.GamerProfile` instance
        '''
        url = 'https://profile.xboxlive.com/users/gt(%s)/profile/settings' % gamertag
        try:
            return cls._fetch(url)
        except GamertagNotFound:
            raise GamertagNotFound('No such user: %s' % gamertag)