[Python] Enumerating all possible lists (of any length) of non-negative integers

I would like to generate/enumerate all possible lists of non-negative integers such that the algorithm will generate lists like the following at some point

[1]
[24542,0]
[245,904609,848,24128,350,999]


In other words, for all possible non-negative integers, generate all possible lists which contain that many non-negative integers.

I have figured that the trick for a list with two numbers is to enumerate their values diagonally like this

first value\second value 0 1 2 3
0 0 (this will be generated first) 2 (this third etc.) 5 9
1 1 (this second) 4 8
2 3 7
3 6

def genpair():
x = 0
y = 0
yield x,y
maxx = 0
while True:
maxx += 1
x = maxx
y = 0
while x >= 0:
yield x,y
x -= 1
y += 1

gen = genpair()

for i in range(10):
print(next(gen))


But does the same trick (or another) also make this work for lists of arbitrary length?

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