You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: common.go
    path of file: ./repos/feishu-openai/code/services/openai
    
    the code of the file until where you have to start completion: package openai

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"mime/multipart"
	"net/http"
	"net/url"
	"start-feishubot/initialization"
	"start-feishubot/logger"
	"start-feishubot/services/loadbalancer"
	"strings"
	"time"
)

type PlatForm string

const (
	MaxRetries = 3
)
const (
	AzureApiUrlV1 = "openai.azure.com/openai/deploymen
    
func GetProxyClient(proxyString string) (*http.Client, error) {
	var client *http.Client
	timeOutDuration := time.Duration(initialization.GetConfig().OpenAIHttpClientTimeOut) * time.Second
	if proxyString == "" {
		client = &http.Client{Timeout: timeOutDuration}
	} else {
		proxyUrl, err := url.Parse(proxyString)
		if err != nil {
			return nil, err
		}
		transport := &http.Transport{
			Proxy: http.ProxyURL(proxyUrl),
		}
		client = &http.Client{
			Transport: transport,
			Timeout:   timeOutDuration,
		}
	}
	return client, nil
}