intelligible errors on schema creation.

トレースバックは graphene/types/schema.py、graphene/types/typemap.py、graphql/type/definition.py を示しています。まず、スキーマの作成から Query フィールドの検証までを追跡してください。エラーで無効な Query/ObjectType クラスを特定できるようにし、結果として生成される例外にその名前が含まれていることを確認してください。

When creating a schema, if there is a problem with one of your QueryObjects, the resulting error message and traceback does not give any indication as to which ObjectType class is broken.

ex)

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/home/user/sonicsd/src/api/graphql.py", line 30, in schema
  File "/usr/local/lib/python3.7/dist-packages/graphene/types/schema.py", line 78, in __init__
    self.build_typemap()
  File "/usr/local/lib/python3.7/dist-packages/graphene/types/schema.py", line 168, in build_typemap
    initial_types, auto_camelcase=self.auto_camelcase, schema=self
  File "/usr/local/lib/python3.7/dist-packages/graphene/types/typemap.py", line 80, in __init__
    super(TypeMap, self).__init__(types)
  File "/usr/local/lib/python3.7/dist-packages/graphql/type/typemap.py", line 31, in __init__
    self.update(reduce(self.reducer, types, OrderedDict()))  # type: ignore
  File "/usr/local/lib/python3.7/dist-packages/graphene/types/typemap.py", line 88, in reducer
    return self.graphene_reducer(map, type)
  File "/usr/local/lib/python3.7/dist-packages/graphene/types/typemap.py", line 117, in graphene_reducer
    return GraphQLTypeMap.reducer(map, internal_type)
  File "/usr/local/lib/python3.7/dist-packages/graphql/type/typemap.py", line 109, in reducer
    field_map = type_.fields
  File "/usr/local/lib/python3.7/dist-packages/graphql/pyutils/cached_property.py", line 22, in __get__
    value = obj.__dict__[self.func.__name__] = self.func(obj)
  File "/usr/local/lib/python3.7/dist-packages/graphql/type/definition.py", line 198, in fields
    return define_field_map(self, self._fields)
  File "/usr/local/lib/python3.7/dist-packages/graphql/type/definition.py", line 217, in define_field_map
    ).format(type_)
AssertionError: Query fields must be a mapping (dict / OrderedDict) with field names as keys or a function which returns such a mapping.

In the error there should at least be the name of the Query class whose fields are invalid.
In this case I believe the error turned out to be that the root Query had no fields because I was improperly dynamically generating them.