def inherit_config(child, parent, keys):
    """
    If a key in keys does not exist in child, assigns the key-value in parent to
        child.
    """
    for key in keys:
        if key not in child.keys():
            child[key] = parent[key]
            print(
                "{} not found in io.yaml file, falling back to main config".format(key)
            )

    return child