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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 enable( self, cmd="enable", pattern="password", re_flags=re.IGNORECASE, default_username="manager", ):
 """Enter enable mode"""

        if self.check_enable_mode():
            return ""
        output = self.send_command_timing(cmd)
        if (
            "username" in output.lower()
            or "login name" in output.lower()
            or "user name" in output.lower()
        ):
            output += self.send_command_timing(default_username)
        if "password" in output.lower():
            output += self.send_command_timing(self.secret)
        log.debug("{}".format(output))
        self.clear_buffer()
        return output