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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_ehlo_lines(self):
 """Return the capabilities to be advertised after EHLO."""

        lines = []
        if self._authenticator != None:
            # TODO: Make the authentication pluggable but separate mechanism
            # from user look-up.
            lines.append('AUTH PLAIN')
        if self._policy != None:
            lines.extend(self._policy.ehlo_lines(self._message.peer))
        lines.append('HELP')
        return lines