有什么办法可以在Python中打印错误消息？

Question

我正在使用python代码打印错误消息，但不会返回。

数据文件Google表格。

https://docs.google.com/spreadsheets/d/1Vq8lGNjVIN_oVSN5fS8dIH5In4-vcpSB5IxxDAP5SzI/edit?usp=sharing

Error message code

如果建议属于目标变量，则将其打印出来，否则给出错误但实际上没有发生。

from rdkit import Chem
from rdkit.Chem import Draw

import pandas as pd
from flask import Flask, jsonify, request, abort
import json
import sys
import random
import unicodedata
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.metrics.pairwise import cosine_similarity

data = pd.read_csv("clean_o2h.csv", sep=",")


app = Flask(__name__)

@app.route('/', methods=["POST"])



def predict_word():
    print(request.get_json())
    sent = request.get_json()['smiles']
    reactants = data["reactants"].tolist()
    targets = data["targets"].tolist()
    error = ("plese enter correct smiles") 

# TFIDF vector representation
    vectorizer = TfidfVectorizer()
    X = vectorizer.fit_transform(targets)

    test = vectorizer.transform([sent])

#test = vectorizer.transform(["NC1=CC=C2C(COC(N[C@H]3C4=C(CC3)C=CC=C4)=N2)=C1"])

    cosine_similarities = cosine_similarity(test, X).flatten()
    l = []
   # n = ["Result 1","Result 2", "Result 3","Result 4"]

# Extract top 5 similarity records
    similarity = cosine_similarities.argsort()[:-5:-1]
     #print("Top 5 recommendations...")
    for sim in similarity:
    #print(reactants[sim])
       result = reactants[sim]
       l.append(result)
       print(l)

      # output = dict(zip(l,n))
       res = { i : l[i] for i in range(0, len(l) ) }



    #return  jsonify({"Recommendation": res})

    if(sent == targets):
      return jsonify({"Recommendation": res})
    else:
           return jsonify({"Error": error})




if __name__ == '__main__':
    app.run(port='8080')

您可以在图像中看到我放置了随机值，但未打印错误消息。