def nested_dict_exists(dict_, nested_key, separator="|"):
    """Test if nested set of keys exists in nested dictionary."""

    # Separate the nested key.
    keys = nested_key.split(separator)

    for key in keys:
        try:
            dict_ = dict_[key]  # Go to next level of nested dict.
        except KeyError:
            return False  # Nested sub dicts were not found.

    return True