AttributeError: module 'typesystem' has no attribute 'SchemaDefinitions'

[sepulworld]

AttributeError: module 'typesystem' has no attribute 'SchemaDefinitions'

[sepulworld]

Here is my Pipenv

[[source]]
url = "https://pypi.org/simple"
verify_ssl = true
name = "pypi"

[packages]
responder = "==2.0.5"
graphene = "==2.1.7"
graphql-core = "==2.2"
graphql-relay = "==2.0.0"
graphql-server-core = "==1.1.1"
aiohttp = "==3.6.2"
redis = "==3.2.1"
prometheus_client = "==0.7.1"
dnspython = "==1.16.0"
kubernetes_asyncio = "==10.0.1"
boto3 = "==1.12.15"
datadog = "==0.38.0"
ddtrace = "==0.41.0"

[dev-packages]
pylint = "*"
pytest = "*"
ipython = "*"
autopep8 = "*"
flake8 = "*"

[requires]
python_version = "3.8"

[pipenv]
allow_prereleases = true

Using latest responder release.

[sepulworld]

Ah, I think I found the issue. I need to set "allow_prereleases" to false.

Saw encode/apistar#675 and #430

[pipenv]
allow_prereleases = false