langchain/model_laboratory.py/ModelLaboratory/__init__
class ModelLaboratory:    def __init__(self, chains: Sequence[Chain], names: Optional[List[str]] = None):
        """Initialize with chains to experiment with.

        Args:
            chains: list of chains to experiment with.
        """
        for chain in chains:
            if not isinstance(chain, Chain):
                raise ValueError(
                    "ModelLaboratory should now be initialized with Chains. "
                    "If you want to initialize with LLMs, use the `from_llms` method "
                    "instead (`ModelLaboratory.from_llms(...)`)"
                )
            if len(chain.input_keys) != 1:
                raise ValueError(
                    "Currently only support chains with one input variable, "
                    f"got {chain.input_keys}"
                )
            if len(chain.output_keys) != 1:
                raise ValueError(
                    "Currently only support chains with one output variable, "
                    f"got {chain.output_keys}"
                )
        if names is not None:
            if len(names) != len(chains):
                raise ValueError("Length of chains does not match length of names.")
        self.chains = chains
        chain_range = [str(i) for i in range(len(self.chains))]
        self.chain_colors = get_color_mapping(chain_range)
        self.names = names