poly_ints ¶Addition, subtraction, negation and bit inversion all work normally for
poly_ints. Multiplication by a constant multiplier and left
shifting by a constant shift amount also work normally. General
multiplication of two poly_ints is not supported and is not
useful in practice.
Other operations are only conditionally supported: the operation might succeed or might fail, depending on the inputs.
This section describes both types of operation.