연결이 안됩니다

작성한 코드 및 에러 메세지

from flask import Flask, render_template, request, jsonify
app = Flask(__name__)

from pymongo import MongoClient
import certifi
ca = certifi.where()
client = MongoClient('ongodb+srv://test:sparta@cluster0.62cdhto.mongodb.net/?retryWrites=true&w=majority', tlsCAFile=ca)
db = client.dbsparta


@app.route('/')
def home():
    return render_template('index.html')

@app.route("/mars", methods=["POST"])
def web_mars_post():
    name_receive = request.form['name_give']
    address_receive = request.form['address_give']
    size_receive = request.form['size_give']
    doc = {
        'name' : name_receive,
        'address' : address_receive,
        'size' : size_receive
        }

    db.mars.insert_one(doc)

    return jsonify({'msg': '주문완료'})

@app.route("/mars", methods=["GET"])
def web_mars_get():
    return jsonify({'msg': 'GET 연결 완료!'})

if __name__ == '__main__':
    app.run('0.0.0.0', port=5000, debug=True)

/Users/9mean2/Desktop/Sparta/projects/mars/venv/bin/python /Users/9mean2/Desktop/Sparta/projects/mars/app.py 

Traceback (most recent call last):

 File "/Users/9mean2/Desktop/Sparta/projects/mars/app.py", line 5, in <module>

  import certifi

ModuleNotFoundError: No module named 'certifi'

종료 코드 1(으)로 완료된 프로세스