Write a function, numbered_rows, which takes one optional parameter, levels. Default values for this parameter is set to 10. Your function should print a pattern shown in doctests.

def numbered_rows (levels = 10):

"""

>>> numbered_rows()

1 * 1 2 3 4 5 6 7 8 9 10

2 * 2 4 6 8 10 12 14 16 18 20

3 * 3 6 9 12 15 18 21 24 27 30

4 * 4 8 12 16 20 24 28 32 36 40

5 * 5 10 15 20 25 30 35 40 45 50

6 * 6 12 18 24 30 36 42 48 54 60

7 * 7 14 21 28 35 42 49 56 63 70

8 * 8 16 24 32 40 48 56 64 72 80

9 * 9 18 27 36 45 54 63 72 81 90

10 * 10 20 30 40 50 60 70 80 90 100

>>> numbered_rows(4)

1 * 1 2 3 4

2 * 2 4 6 8

3 * 3 6 9 12

4 * 4 8 12 16

"""