f"The input key {input_key} was also found in the memory keys "
                f"({memory_keys}) - please provide keys that don't overlap."
            )
        prompt_variables = values["prompt"].input_variables
        expected_keys = memory_keys + [input_key]
        if set(expected_keys) != set(prompt_variables):
            raise ValueError(
                "Got unexpected prompt input variables. The prompt expects "
                f"{prompt_variables}, but got {memory_keys} as inputs from "
                f"memory, and {input_key} as the normal input key."
            )
        return values