Issue with SQLModel model_dump Serialization in _serialize_json

[adunato]

Issue you'd like to raise.

Langsmith Version: 0.1.130
SQLModel Version: 0.0.22

Description:

I'm encountering an issue with the _serialize_json method when using SQLModel in conjunction with the Langsmith library. The problem arises when the model_dump() method is called on an SQLModel class rather than an instance, leading to a TypeError due to the missing required self argument.

Steps to Reproduce:

Create an SQLModel class.
Attempt to serialize an SQLModel class or instance using the _serialize_json function.
If an SQLModel class (not an instance) is passed, the error is raised.

Error logs:
Failed to use model_dump to serialize <class 'sqlmodel.main.SQLModelMetaclass'> to JSON: TypeError("SQLModel.model_dump() missing 1 required positional argument: 'self'")
Failed to use dict to serialize <class 'sqlmodel.main.SQLModelMetaclass'> to JSON: TypeError("SQLModel.dict() missing 1 required positional argument: 'self'")
...

This occurs because the _serialize_json method attempts to call model_dump() on an SQLModelMetaclass rather than an instance of the SQLModel.

Suggestion:

Potential Solution: Modify the _serialize_json method to ensure that model_dump() is only called on instances of SQLModel, not the class itself. Here's a possible update to prevent this issue:

`def _serialize_json(obj: Any) -> Any:
try:
if isinstance(obj, (set, tuple)):
if hasattr(obj, "_asdict") and callable(obj._asdict):
# NamedTuple
return obj._asdict()
return list(obj)

    # Ensure we are working with an instance, not a class
    if isinstance(obj, type):
        return repr(obj)

    serialization_methods = [
        ("model_dump", True),  # Pydantic V2 with non-serializable fields
        ("dict", False),  # Pydantic V1 with non-serializable fields
        ("to_dict", False),  # dataclasses-json
    ]
    for attr, exclude_none in serialization_methods:
        if hasattr(obj, attr) and callable(getattr(obj, attr)):
            try:
                method = getattr(obj, attr)
                return (
                    method(exclude_none=exclude_none) if exclude_none else method()
                )
            except Exception as e:
                logger.error(
                    f"Failed to use {attr} to serialize {type(obj)} to"
                    f" JSON: {repr(e)}"
                )
                pass
    return _simple_default(obj)
except BaseException as e:
    logger.debug(f"Failed to serialize {type(obj)} to JSON: {e}")
    return repr(obj)

`

This modification checks whether the object passed to _serialize_json is a class or an instance before attempting to call model_dump.

Environment:

Python Version: [please provide]
SQLModel Version: [please provide]
Langsmith Version: [please provide]
Let me know if any other information is needed!