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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 do_GET(self):
 """ Process validation GET requests. All modes of validation (OTP, OATH and PWHASH) must be explicitly enabled in `args' to be allowed. """

        if self.path.startswith(args.serve_url):
            res = None
            log_res = None
            mode = None
            params = urlparse.parse_qs(self.path[len(args.serve_url):])
            if "otp" in params:
                if args.mode_short_otp:
                    # YubiKey internal db OTP in KSM mode
                    mode = 'YubiKey OTP (short)'
                    res = validate_yubikey_otp_short(self, params)
                elif args.mode_otp:
                    # YubiKey internal db OTP validation 2.0
                    mode = 'YubiKey OTP'
                    res = validate_yubikey_otp(self, params)
                    #status = [x for x in res.split('\n') if x.startswith("status=")]
                    #if len(status) == 1:
                    #    res = status[0][7:]
                    log_res = '&'.join(res.split('\n'))
                else:
                    res = "ERR 'otp/otp2' disabled"
            elif "hotp" in params:
                if args.mode_hotp:
                    mode = 'OATH-HOTP'
                    res = validate_oath_hotp(self, params)
                else:
                    res = "ERR 'hotp' disabled"
            elif "totp" in params:
                if args.mode_totp:
                    mode = 'OATH-TOTP'
                    res = validate_oath_totp(self, params)
                else:
                    res = "ERR 'totp' disabled"
            elif "pwhash" in params:
                if args.mode_pwhash:
                    mode = 'Password hash'
                    res = validate_pwhash(self, params)
                else:
                    res = "ERR 'pwhash' disabled"

            if not log_res:
                log_res = res

            self.log_message("%s validation result: %s -> %s", mode, self.path, log_res)

            if res != None:
                self.send_response(200)
                self.send_header('Content-type', 'text/plain')
                self.end_headers()
                self.wfile.write(res)
                self.wfile.write("\n")
            else:
                self.log_error ("No validation result to '%s' (responding 403)" % (self.path))
                self.send_response(403, 'Forbidden')
                self.end_headers()
        else:
            self.log_error ("Bad URL '%s' - I'm serving '%s' (responding 403)" % (self.path, args.serve_url))
            self.send_response(403, 'Forbidden')
            self.end_headers()