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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 get_assignee(self, login):
 """ given the user login, looks for a user in assignee list of the repo and return it if was found. """

        if not login:
            return GithubObject.NotSet
        if not hasattr(self, '_assignees'):
            self._assignees = {c.login: c for c in self.repo.get_assignees()}
        if login not in self._assignees:
            # warning
            print("{} doesn't belong to this repo. This issue won't be assigned.".format(login))
        return self._assignees.get(login)