Colander and None?

none-nested-sequence.py

import colander


class NoneSequence(colander.MappingSchema):
    foo = colander.SchemaNode(colander.String())
    bar = colander.SchemaNode(
        colander.Sequence(), colander.SchemaNode(colander.String()),
        missing=None)


class NestedNoneSequence(colander.MappingSchema):
    a = colander.SchemaNode(colander.String())
    b = NoneSequence()

schema = NestedNoneSequence()
deserialized = schema.deserialize({"a": "a", "b": {"foo": "abc", "bar": None}})
# colander.Invalid: {'b.bar': '"None" is not iterable'}

none-nested-tuple.py

import colander


class Tuple(colander.TupleSchema):
    val1 = colander.SchemaNode(colander.String())
    val2 = colander.SchemaNode(colander.Int())


class TupleSchema(colander.MappingSchema):
    t = Tuple(missing=None)


class NestedTupleSchema(colander.MappingSchema):
    n = TupleSchema()

schema = NestedTupleSchema()
print(schema.deserialize({"n": {"t": ["s", 1]}}))
# {'b': {'a': {'val': 'ok'}}}

print(schema.deserialize({"n": {"t": None}}))
# colander.Invalid: {'n.t': '"None" is not iterable'}

none-nested.py

import colander


class SchemaA(colander.MappingSchema):
    val = colander.SchemaNode(colander.String())


class SchemaB(colander.MappingSchema):
    a = SchemaA(missing=None)


class BodySchemaC(colander.MappingSchema):
    b = SchemaB()

schema = BodySchemaC()
print(schema.deserialize({"b": {"a": {"val": "ok"}}}))
# {'b': {'a': {'val': 'ok'}}}

print(schema.deserialize({"b": {"a": None}}))
# colander.Invalid: {'b.a': '"None" is not a mapping type: Does not implement dict-like functionality.'}

none-sequence.py

import colander


class NoneSequence(colander.MappingSchema):
    foo = colander.SchemaNode(colander.String())
    bar = colander.SchemaNode(
        colander.Sequence(), colander.SchemaNode(colander.String()),
        missing=None)

schema = NoneSequence()
deserialized = schema.deserialize({'foo': '1', 'bar': None})
# colander.Invalid: {'bar': '"None" is not iterable'}

none.py

import colander


class Person(colander.MappingSchema):
    name = colander.SchemaNode(colander.String(), missing=None)

schema = Person()
deserialized = schema.deserialize({'name': None})
print(deserialized)
# {'name': None}