system.dataset.addRows(dataset [, rowIndex], rows)
Dataset dataset - The starting dataset. Please be aware that this dataset will not actually be modified (datasets are immutable), but rather will be the starting point for creating a new dataset.
int rowIndex - The index (starting at 0) at which to insert the new row. Will throw an IndexError if less than zero or greater than the length of the dataset. If omitted, the new row will be appended to the end. [optional]
PySequence rows - A Python sequence of sequences representing the data for the new rows. The length of each sequence must equal the number of columns in the dataset.
Dataset - A new dataset with the new rows inserted or appended.