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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 pair(self):
 """Get the name and value for this environment variable"""

        if self.set_val is not None:
            return self.env_name, self.set_val
        elif self.default_val is not None:
            return self.env_name, os.environ.get(self.env_name, self.default_val)
        else:
            return self.env_name, os.environ[self.env_name]