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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:
 async def help(self, command_name=None):
 """ Sends a SMTP 'HELP' command. For further details please check out `RFC 5321 § 4.1.1.8`_. Args: command_name (str or None, optional):
 Name of a command for which you want help. For example, if you want to get help about the '*RSET*' command, you'd call ``help('RSET')``. Raises: ConnectionResetError: If the connection with the server is unexpectedely lost. SMTPCommandFailedError: If the HELP command fails. Returns: Help text as given by the server. .. _`RFC 5321 § 4.1.1.8`: https://tools.ietf.org/html/rfc5321#section-4.1.1.8 """

        if command_name is None:
            command_name = ""

        code, message = await self.do_cmd("HELP", command_name)

        return message