Столкнулся с проблемой при создании бота ChatGpt для telegram на Golang

package main

import (
    "context"
    "fmt"
    "log"
    "strings"

    tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api"
    gogpt "github.com/sashabaranov/go-gpt3"
    "github.com/spf13/viper"
)

type Config struct {
    TelegramToken string `mapstructure:"tgToken"`
    GptToken      string `mapstructure:"gptToken"`
}

type GptBotStruct struct {
    MaxTokensGpt int
    NameBot      string
}

func LoadConfig(path string) (c Config, err error) {
    viper.SetConfigName("config")
    viper.SetConfigType("yaml")
    viper.AddConfigPath(path)

    viper.AutomaticEnv()

    err = viper.ReadInConfig()

    if err != nil {
        return
    }

    err = viper.Unmarshal(&c)
    return
}

func sendChatGPT(c *gogpt.Client, sendText string, gptM GptBotStruct) string {
    ctx := context.Background()

    req := gogpt.CompletionRequest{
        Model:            gptM.NameBot,
        MaxTokens:        gptM.MaxTokensGpt,
        Prompt:           sendText,
        FrequencyPenalty: 0,
        PresencePenalty:  0,
    }

    resp, err := c.CreateCompletion(ctx, req)
    if err != nil {
        return "ChatGPT API error"
    } else {
        return resp.Choices[0].Text
    }
}

func main() {
    // Reading config.yaml
    config, err := LoadConfig(".")

    if err != nil {
        panic(fmt.Errorf("fatal error with config.yaml: %w", err))
    }

    // Chat GPT initialization
    chatGPT := gogpt.NewClient(config.GptToken)

    // Telegram initialization
    bot, err := tgbotapi.NewBotAPI(config.TelegramToken)
    if err != nil {
        log.Panic(err)
    }

    bot.Debug = true // set to false for suppress logs in stdout
    log.Printf("Authorized on account %s", bot.Self.UserName)

    // Start Telegram long polling update
    u := tgbotapi.NewUpdate(0)
    u.Timeout = 5
    updates, _ := bot.GetUpdatesChan(u)

    GptMode := GptBotStruct{
        MaxTokensGpt: 3000,
        NameBot:      "text-davinci-003",
    }

    //Check message in updates
    for update := range updates {
        if update.Message == nil {
            continue
        }

        checkOne := strings.HasPrefix(update.Message.Text, "/text")
        checkTwo := strings.HasPrefix(update.Message.Text, "/code")
        checkThree := strings.HasPrefix(update.Message.Text, "/curie")
        if checkOne || checkTwo || checkThree {
            if checkOne {
                GptMode.MaxTokensGpt = 3000
                GptMode.NameBot = "text-davinci-003"
            } else if checkTwo {
                GptMode.MaxTokensGpt = 4096
                GptMode.NameBot = "code-davinci-002"
            } else {
                GptMode.MaxTokensGpt = 2048
                GptMode.NameBot = "text-curie-001"
            }
            update.Message.Text = "Вы выбрали режим " + GptMode.NameBot
        } else {
            update.Message.Text = sendChatGPT(chatGPT, update.Message.Text, GptMode)
        }

        // Send message to Telegram
        msg := tgbotapi.NewMessage(update.Message.Chat.ID, update.Message.Text)
        msg.ReplyToMessageID = update.Message.MessageID

        _, err = bot.Send(msg)
        if err != nil {
            log.Println("Error:", err)
        }
    }
}

При смене режима бота возвращает ошибку:

return "ChatGPT API error"