failed test case?

I tried this test case which i can manually verify it's valid:

```a b c = triangle12 a b c; d e f g = centroid d e f g b a c; h = s_angle c b h 30; i = intersection_lt i d h c g a```

but when running through DDAR I got the `numericals.InvalidLineIntersectError`:

```Traceback (most recent call last):
File "", line 1, in
File "/root/code/alphageometry/ddar.py", line 95, in solve
dervs, eq4, next_branches, added = saturate_or_goal(
File "/root/code/alphageometry/ddar.py", line 50, in saturate_or_goal
added, derv, eq4, n_branching = dd.bfs_one_level(
File "/root/code/alphageometry/dd.py", line 1094, in bfs_one_level
add = g.add_piece(name, args, deps=deps)
File "/root/code/alphageometry/graph.py", line 697, in add_piece
return self.add_cyclic(args, deps)
File "/root/code/alphageometry/graph.py", line 1524, in add_cyclic
circle = self.get_new_circle_thru_triplet(p1, p2, p3)
File "/root/code/alphageometry/graph.py", line 869, in get_new_circle_thru_triplet
circle.num = nm.Circle(p1=p1.num, p2=p2.num, p3=p3.num)
File "/root/code/alphageometry/numericals.py", line 409, in __init__
center = line_line_intersection(l12, l23)
File "/root/code/alphageometry/numericals.py", line 586, in line_line_intersection
raise InvalidLineIntersectError
numericals.InvalidLineIntersectError```

does anyone know if this is a known bug in DDAR?