from typing import Callable


def find_function_in_object(o: object, function_name: str) -> Callable:
    """Finds a callable object matching given function name in given object.

    Args:
        o: Any object.
        function_name: Name of attribute within o.

    Returns:
        Callable object with name <function_name> in object <o>.

    Raises:
        LookupError: if <function_Name> is not a callable object in <o>.
    """
    try:
        function_handle = getattr(o, function_name)
        if not hasattr(function_handle, "__call__"):
            raise LookupError(
                f"Resolved object {function_name} in object {o} is not a function."
            )
        else:
            return function_handle
    except AttributeError:
        raise LookupError(f"Cannot find function {function_name} in object {o}.")