def METHOD_NAME(matrix: Union[List[List[MatrixData]], str], values: Dict[str, Any]) -> str:
    """
    Validates the matrix, stores the matrix array in the matrices repository,
    and returns a reference to the stored array.
    Args:
        matrix: The matrix data or matrix link to validate.
        values: Additional values used during the validation process.
            It should contain the following key-value pairs:
            - "command_context": An object providing access to matrix services.
              It should have a "matrix_service" attribute which allows creating
              and checking the existence of matrices.
    Returns:
        The ID of the validated matrix prefixed by "matrix://".
    Raises:
        TypeError: If the provided matrix is neither a matrix nor a link to a matrix.
        ValueError: If the matrix ID does not exist.
    """
    matrix_service: ISimpleMatrixService = values["command_context"].matrix_service
    if isinstance(matrix, list):
        return MATRIX_PROTOCOL_PREFIX + matrix_service.create(data=matrix)
    elif isinstance(matrix, str):
        if matrix_service.exists(matrix):
            return MATRIX_PROTOCOL_PREFIX + matrix
        else:
            raise ValueError(f"Matrix with id {matrix} does not exist")
    else:
        raise TypeError(f"The data {matrix} is neither a matrix nor a link to a matrix")