from typing import Any, Dict, List, Optional, Sequence

class YourClass:
    MAX_TOP_N = 99  # Example maximum value for top_n

    def __new__(cls, model_type=None, model_name='default_model',
                 model_credential: Dict[str, object] = {}, **kwargs):
        return cls.new_instance(
            model_type=model_type, model_name=model_name,
            model_credential=model_credential, **kwargs
        )

    @classmethod
    def new_instance(cls, model_type, model_name, model_credential: Dict[str, object], **kwargs) -> 'YourClass':
        top_n = kwargs.setdefault('top_n', cls.MAX_TOP_N)

        instance = super().__new__(cls)
        instance.init(model_type, model_name, model_credential, top_n=top_n)
        return instance

    def init(self, api_base: Optional[str] = None, model: Optional[str] = None, top_n: int = 3,
             api_key: Optional[str] = None):
        if not api_base:
            raise ValueError("Please provide server URL")
        
        if not model:
            raise ValueError("Please provide the model name")

        if not api_key:
            raise ValueError("Please provide the API key")

        self.api_base = api_base
        self.model = model
        self.api_key = api_key
        self.top_n = min(top_n, self.MAX_TOP_N)

    def compress_documents(self, documents: Sequence[Document], query: str, callbacks: Optional['Callbacks'] = None) -> Sequence[Document]:
        """Compresses a list of documents."""
        if not documents:
            return []

        # Placeholder for document compression logic
        compressed_docs = []  # Replace this with actual implementation
        for doc in documents:
            # Simulate compression process
            compressed_docs.append(doc.compress(query))
        return compressed_docs[:]