错误：'dagster.core.types类型.runtime不是包

Question

第一次在conda环境中安装dagster，并尝试运行airline演示，如here所述。以下是我遵循的步骤。你知道吗

conda env create -n dagster python=3.7
conda activate dagster
pip install dagster dagit
git clone git@github.com/dagster-io/dagster.git
cd dagster/examples
pip install -e '[.full]'
docker-compose up -d
cd dagster_examples/airline_demo
dagit

然后，我得到以下以'dagster.core.types.runtime' is not a package消息结尾的堆栈跟踪：

Loading repository...
Traceback (most recent call last):
  File "/Users/timrozmajzl/miniconda3/envs/dagster/bin/dagit-cli", line 8, in <module>
    sys.exit(main())
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagit/cli.py", line 110, in main
    cli = create_dagit_cli()
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagit/cli.py", line 21, in create_dagit_cli
    return ui(auto_envvar_prefix='DAGIT')  # pylint: disable=no-value-for-parameter
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagit/cli.py", line 72, in ui
    host_dagit_ui(handle, host, port, storage_fallback, reload_trigger)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagit/cli.py", line 81, in host_dagit_ui
    app = create_app(handle, instance, reloader)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagit/app.py", line 160, in create_app
    version=__version__,
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagster_graphql/implementation/context.py", line 17, in __init__
    self.repository_definition = self.get_handle().build_repository_definition()
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagster/core/definitions/handle.py", line 392, in build_repository_definition
    obj = self.entrypoint.perform_load()
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagster/core/definitions/handle.py", line 445, in entrypoint
    return self.data.get_repository_entrypoint(from_handle=self)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagster/core/definitions/handle.py", line 522, in get_repository_entrypoint
    return LoaderEntrypoint.from_yaml(self.repository_yaml, from_handle=from_handle)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagster/core/definitions/handle.py", line 175, in from_yaml
    return LoaderEntrypoint.from_module_target(module_name, fn_name, from_handle)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/site-packages/dagster/core/definitions/handle.py", line 161, in from_module_target
    module = importlib.import_module(module_name)
  File "/Users/timrozmajzl/miniconda3/envs/dagster/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/Users/timrozmajzl/Projects/dagster/dagster/examples/dagster_examples/airline_demo/repository.py", line 3, in <module>
    from .pipelines import define_airline_demo_ingest_pipeline, define_airline_demo_warehouse_pipeline
  File "/Users/timrozmajzl/Projects/dagster/dagster/examples/dagster_examples/airline_demo/pipelines.py", line 14, in <module>
    from .resources import postgres_db_info_resource, redshift_db_info_resource
  File "/Users/timrozmajzl/Projects/dagster/dagster/examples/dagster_examples/airline_demo/resources.py", line 3, in <module>
    from .types import DbInfo
  File "/Users/timrozmajzl/Projects/dagster/dagster/examples/dagster_examples/airline_demo/types.py", line 8, in <module>
    from dagster.core.types.runtime.runtime_type import create_string_type
ModuleNotFoundError: No module named 'dagster.core.types.runtime.runtime_type'; 'dagster.core.types.runtime' is not a package