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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 version_str(self):
 """ The version string for the currently-running awslimitchecker; includes git branch and tag information. :rtype: str """

        vs = str(self.release)
        if self.tag is not None:
            vs += '@{t}'.format(t=self.tag)
        elif self.commit is not None:
            vs += '@{c}'.format(c=self.commit)
        return vs