Resolved: Error No file found while converting file present in s3 using boto3

import boto3
import csv
import json

# set up S3 connection
s3 = boto3.resource('s3')

my_bucket = s3.Bucket('csvfolder3')
# bucket_name = 'csvfolder3'

def lambda_handler(event, context):

    for file in my_bucket.objects.all():
        print(file.key)
        body = file.get()['Body'].read()
        print(body)
        with open(file.key, 'r') as csvfile: #####[ERROR] FileNotFoundError: [Errno 2] No such file or directory: 'data.csv'

            data = [row for row in csv.DictReader(csvfile)]
            json_data = json.dumps(data)
        s3.Object(my_bucket, 'file.json').put(Body=json_data)

body = file.get()['Body'].read()

bytes_data.decode()

StringIO(...)

from __future__ import annotations

import csv
import json
from io import StringIO

byte_content = b"""
id,name,age,height,weight
1,Alice,20,62,120.6
2,Freddie,21,74,190.6
3,Bob,17,68,120.0
""".strip()

# set encoding if known
encoding = 'utf-8'

# decode bytes -> str
content = byte_content.decode(encoding)

# create file-like object
file = StringIO(content)

data: list[dict] = [row for row in csv.DictReader(file, delimiter=",")]

json_data: str = json.dumps(data, indent=2)
print(json_data)

[
  {
    "id": "1",
    "name": "Alice",
    "age": "20",
    "height": "62",
    "weight": "120.6"
  },
  {
    "id": "2",
    "name": "Freddie",
    "age": "21",
    "height": "74",
    "weight": "190.6"
  },
  {
    "id": "3",
    "name": "Bob",
    "age": "17",
    "height": "68",
    "weight": "120.0"
  }
]