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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 sasl_plain(self, name, password, identity=None):
 """Authenticate to a server using SASL plain, or does so on connection. Args: name (str):
 Name to auth with. password (str):
 Password to auth with. identity (str):
 Identity to auth with (defaults to name). """

        if identity is None:
            identity = name

        self.sasl('plain', name, password, identity)