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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 capability(self):
 """Ask server capabilities. See MANAGESIEVE specifications, section 2.4 This command does not affect capabilities recorded by this client. :rtype: string """

        code, data, capabilities = (
            self.__send_command("CAPABILITY", withcontent=True))
        if code == "OK":
            return capabilities
        return None