无法从pyramid.config导入Configurator

Question

第一次使用Pyramid，我有以下代码：

# -*- coding: utf-8 -*-
import os
import logging
import psycopg2
from contextlib import closing
from pyramid.config import Configurator
from pyramid.session import SignedCookieSessionFactory
from pyramid.view import view_config
from waitress import serve

TABLE1_SCHEMA = """
CREATE TABLE IF NOT EXISTS days (
    date DATE PRIMARY KEY,
    dow SMALLINT NOT NULL)
"""

TABLE2_SCHEMA = """
CREATE TABLE IF NOT EXISTS events (
    id serial PRIMARY KEY,
    description TEXT NOT NULL,
    date DATE REFERENCES days(date) NOT NULL,
    time TIME NOT NULL)
"""

logging.basicConfig()
log = logging.getLogger(__file__)


@view_config(route_name='home', renderer='string')
def home(request):
    return "Hello World"


def connect_db(settings):
    """Return a connection to the configured database"""
    return psycopg2.connect(settings['db'])


def init_db():
    """
    Create database tables defined by TABLE1_SCHEMA and TABLE2_SCHEMA
    Warning: This function will not update existing table definitions
    """
    settings = {}
    settings['db'] = os.environ.get(
        'DATABASE_URL', 'dbname=calendar_db user=store'
    )
    with closing(connect_db(settings)) as db:
        db.cursor().execute(TABLE1_SCHEMA)
        db.cursor().execute(TABLE2_SCHEMA)
        db.commit()


def main():
    """Create a configured wsgi app"""
    settings = {}
    settings['reload_all'] = os.environ.get('DEBUG', True)
    settings['debug_all'] = os.environ.get('DEBUG', True)
    settings['db'] = os.environ.get(
        'DATABASE_URL', 'dbname=calendar_db user=store'
    )
    # secret value for session signing:
    secret = os.environ.get('CALENDAR_SESSION_SECRET', 'secret')
    session_factory = SignedCookieSessionFactory(secret)
    # configuration setup
    config = Configurator(
        settings=settings,
        session_factory=session_factory
    )
    config.add_route('home', '/')
    config.scan()
    app = config.make_wsgi_app()
    return app

if __name__ == '__main__':
    app = main()
    port = os.environ.get('PORT', 5000)
    serve(app, host='0.0.0.0', port=port)

我试图让Heroku＆＃39;工头开始＆＃39;命令。我收到以下错误：＆＃39; ImportError：无法导入名称配置器＆＃39; 我不知道问题可能是什么。请帮忙！