def get_from_module(module_params, module_name, identifier):
    """Gets a class/instance of a module member specified by the identifier.

    Args:
        module_params: dict, contains identifiers
        module_name: str, containing the name of the module
        identifier: str, specifying the module member

    Returns:
        a class or an instance of a module member specified
        by the identifier
    """
    res = module_params.get(identifier.lower())
    if res is None:
        raise ValueError("Invalid {} identifier!".format(module_name), identifier)
    return res