Question: how to draw an image like this in python where...

How to draw an image like this in python where the number of rows is dependant on n? in this case the n =7

Could you also explain what each line of code does in drawing

Example starter code from pdf textbook below

n = int(input("Choose a number: "))
for row in range(n):
    for column in range(row+1):
        print('*', end='')
    print()