How to make a url redirect in flask outside of @app.route

Question

I’m trying to consume a free market api using Python along with flask, to be able to use this API, I need to generate a token and to generate a token, I need a client authorization code, ie, will open a tab to put the user and password for my application get the code, I’m doing it like this:

@app.route('/code')
def code():
    print('Gerando um novo code')
    return redirect('https://auth.mercadolivre.com.br/authorization?response_type=code&client_id=*********&redirect_uri=https://test/gera_token')

@app.route('/gera_token')
def gera_token():
  
        code = request.args.get('code')
        if code:
            resp = token_principal(code)
            return resp
        else:
            return redirect('O code não foi encontrado')

En route '/code' I will direct the user to authorize my application and en route '/gera_token' I receive the code and call the function that is in another file to generate the token

def token_principal(code):
    

    url = 'https://api.mercadolibre.com/oauth/token'

    header = {
        'accept'       : 'application/json',
        'content-type' : 'application/x-www-form-urlencoded'
    }

    dados = {
        'grant_type' : 'authorization_code' ,
        'client_id' : '********' ,
        'client_secret' : '*************' ,
        'code' : code, 
        'redirect_uri' : 'https://test/gera_token'
    }

    requisicao = requests.post(url,
                            headers = header,
                            data = dados)

    
    return requisicao.text 

This code is working, but I would like to do this whole process in a single function, ie within the function token_principal(), be able to redirect the user to ML pay the code and generate the token.