Python hypothesis: Ensure that input lists have same length

I found an answer using the @composite decorator.

import hypothesis.strategies as st
from hypothesis import given

@st.composite
def same_len_lists(draw):

    n = draw(st.integers(min_value=1, max_value=50))
    fixed_length_list = st.lists(st.integers(), min_size=n, max_size=n)

    return (draw(fixed_length_list), draw(fixed_length_list))


@given(same_len_lists())
def test_my_func(lists):

    x, y = lists

    # Assertions

You can use flatmap to generate data that depends on other generated data.

import hypothesis.strategies as st
from hypothesis import assume, given
from hypothesis.strategies import integers as ints

same_len_lists = ints(min_value=1, max_value=100).flatmap(lambda n: st.lists(st.lists(ints(), min_size=n, max_size=n), min_size=2, max_size=2))

@given(same_len_lists)
def test_my_func(lists):
    x, y = lists
    assume(len(x) == len(y))

It's a little clumsy, and I'm not very happy about having to unpack the lists inside the test body.