I'd like to declare a schema field to accept different schema types, but not any.
Is something like the following possible with Marshmallow?
class SchemaA(Schema):
name = String()
class SchemaB(Schema):
name = String()
age = Integer()
class SchemaC(Schema)
one_of_many_but_not_any = [SchemaA(), SchemaB(), String()] # <- !
What you want to achieve is referred to as polymorphism.
This is not supported by marshmallow yet but it is a recurrent question and I've been tagging all related issues in the bugtracker with the polymorphism tag.
See for instance https://github.com/marshmallow-code/marshmallow/issues/1255.
There are currently two libs adding this support:
They both have their pros/cons.