"""LangChain **Runnable** and the **LangChain Expression Language (LCEL)**. The LangChain Expression Language (LCEL) offers a declarative method to build production-grade programs that harness the power of LLMs. Programs created using LCEL and LangChain Runnables inherently support synchronous, asynchronous, batch, and streaming operations. Support for **async** allows servers hosting the LCEL based programs to scale better for higher concurrent loads. **Batch** operations allow for processing multiple inputs in parallel. **Streaming** of intermediate outputs, as they're being generated, allows for creating more responsive UX. This module contains non-core Runnable classes. """