首先确保安装了moto和boto3模块。 然后，运行下面的代码可以模拟AWS Cognito服务，并使用boto3进行身份验证。

import boto3
from moto import mock_cognito_idp

with mock_cognito_idp():
    client = boto3.client('cognito-idp', region_name='us-west-2')

    app_client = client.create_user_pool_client(
        UserPoolId='us-west-2_TESTUSERPOOL',
        ClientName='test-app-client',
    )

    user = client.admin_create_user(
        UserPoolId='us-west-2_TESTUSERPOOL',
        Username='test-user'
    )

    response = client.initiate_auth(
        ClientId=app_client['UserPoolClient']['ClientId'],
        AuthFlow='USER_PASSWORD_AUTH',
        AuthParameters={
            'USERNAME': 'test-user',
            'PASSWORD': 'Test1234!'
        }
    )

    access_token = response['AuthenticationResult']['AccessToken']

如果你想使用awssrp库，可以试试下面的代码：

import boto3
import awssrp

client = boto3.client('cognito-idp')

user_pool_id = 'us-west-2_TESTUSERPOOL'
client_id = 'xyzabc123def456'
username = 'test-user'
password = 'Test1234!'

aws_cognito = awssrp.AWSSRP(
    username=username,
    password=password,
    pool_id=user_pool_id,
    client_id=client_id,
    client=client
)

tokens = aws_cognito.authenticate_user()
access_token = tokens['AuthenticationResult']['AccessToken']

如果你在本地模拟AWS服务或使用awssrp时遇到问题，请确保按照官方文档操作，并尝试使用最新版本的模块。