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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 template(self, name):
 """ Set an active template to use with our Postman. This changes the call signature of send. Arguments: - `name`: str Return: None Exceptions: None """

        self.plain, self.html = self._find_tpls(name)
        if not self.plain:
            self.plain = self._find_tpl(name)
        try:
            self.send = self._sendtpl
            yield
        finally:
            self.plain, self.html = None, None
            self.send = self._send