langchain/base_language.py/BaseLanguageModel/all_required_field_names
class BaseLanguageModel:    def all_required_field_names(cls) -> Set:
        all_required_field_names = set()
        for field in cls.__fields__.values():
            all_required_field_names.add(field.name)
            if field.has_alias:
                all_required_field_names.add(field.alias)
        return all_required_field_names