def _tikz_representation(array):
    """Returns the pgf/tikz string representation of the array.

    Args:
        array (np.ndarray): The array which requires a string representation.

    Returns:
        str: The pgf/tikz string representation.

    Raises:
        ValueError: If the dimension of the array is not 1 or 2.

    """
    if array.ndim == 1:
        return f"({', '.join(str(c) for c in array)})"
    elif array.ndim == 2:
        return " -- ".join(str(v) for v in array)
    else:
        raise ValueError(
            f"Arrays of dimension {array.ndim} have no TikZ representation."
        )