venv/lib/python3.12/site-packages/sympy/series/benchmarks/bench_order.py

from sympy.core.add import Add
from sympy.core.symbol import Symbol
from sympy.series.order import O

x = Symbol('x')
l = [x**i for i in range(1000)]
l.append(O(x**1001))

def timeit_order_1x():
    Add(*l)