Where is the problem?

What can we do better?

Positive ndigits arg are rounded two digits to the right of the decimal (as in convention in other Python libraries) as the code suggests and performs...
round(1.2345, 2) # returns 1.23

Additionally,
Negative ndigits arg are counted from the decimal to the left
round(12345, -2) # returns 12000

I suggest adding a simple line that makes that explicit.
[Current] "ndigits: The number of digits to round to."
[ADD] Positive to the right of the decimal, negative to the left.

Anything else?

No response