Converts multirow cells to a list of lists and informs the number of lines of each row.

    Returns:
         tuple: new_data, row_heights

def expand_multirow_data(data):
    """
    Converts multirow cells to a list of lists and informs the number of lines of each row.

    Returns:
         tuple: new_data, row_heights
    """

    num_cols = len(data[0]) # number of columns

    # calculates row heights
    row_heights = []
    for mlrow in data:
        row_height = 0
        for j, cell in enumerate(mlrow):
            row_height = max(row_height, 1 if not isinstance(cell, (list, tuple)) else len(cell))
        row_heights.append(row_height)
    num_lines = sum(row_heights) # line != row (rows are multiline)

    # rebuilds table data
    new_data = [[""]*num_cols for i in range(num_lines)]
    i0 = 0
    for row_height, mlrow in zip(row_heights, data):
        for j, cell in enumerate(mlrow):
            if not isinstance(cell, (list, tuple)):
                cell = [cell]

            for incr, x in enumerate(cell):
                new_data[i0+incr][j] = x

        i0 += row_height

    return new_data, row_heights