Exceptions

Exception classes for marshmallow-related errors.

exception marshmallow.exceptions.FieldInstanceResolutionError

Raised when schema to instantiate is neither a Schema class nor an instance.

exception marshmallow.exceptions.MarshmallowError

Base class for all marshmallow-related errors.

exception marshmallow.exceptions.RegistryError

Raised when an invalid operation is performed on the serializer class registry.

exception marshmallow.exceptions.StringNotCollectionError

Raised when a string is passed when a list of strings is expected.

exception marshmallow.exceptions.ValidationError(message, field_name='_schema', data=None, valid_data=None, **kwargs)

Raised when validation fails on a field or schema.

Validators and custom fields should raise this exception.

Parameters:

• message (str | list | dict) – An error message, list of error messages, or dict of error messages. If a dict, the keys are subitems and the values are error messages.

• field_name (str) – Field name to store the error on. If None, the error is stored as schema-level error.

• data (Mapping[str, Any] | Iterable[Mapping[str, Any]] | None) – Raw input data.

• valid_data (list[dict[str, Any]] | dict[str, Any] | None) – Valid (de)serialized data.