> ## Documentation Index
> Fetch the complete documentation index at: https://docs.camel-ai.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Camel.retrievers.base

## \_query\_unimplemented

```python theme={"system"}
def _query_unimplemented(self, *input: Any):
```

Defines the query behavior performed at every call.

Query the results. Subclasses should implement this
method according to their specific needs.

It should be overridden by all subclasses.

.. note::
Although the recipe for forward pass needs to be defined within
this function, one should call the :class:`BaseRetriever` instance
afterwards instead of this since the former takes care of running the
registered hooks while the latter silently ignores them.

## \_process\_unimplemented

```python theme={"system"}
def _process_unimplemented(self, *input: Any):
```

Defines the process behavior performed at every call.

Processes content from a file or URL, divides it into chunks by
using `Unstructured IO`,then stored internally. This method must be
called before executing queries with the retriever.

Should be overridden by all subclasses.

.. note::
Although the recipe for forward pass needs to be defined within
this function, one should call the :class:`BaseRetriever` instance
afterwards instead of this since the former takes care of running the
registered hooks while the latter silently ignores them.

## BaseRetriever

```python theme={"system"}
class BaseRetriever(ABC):
```

Abstract base class for implementing various types of information
retrievers.

### **init**

```python theme={"system"}
def __init__(self):
```


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