imported TraceGraph in poutine/__init__.py
+# poutines
from .block_poutine import BlockPoutine
from .poutine import Poutine # noqa: F401
from .queue_poutine import QueuePoutine
from .replay_poutine import ReplayPoutine
-from .trace import Trace # noqa: F401
from .trace_poutine import TracePoutine
from .tracegraph_poutine import TraceGraphPoutine
+# trace data structures
+from .trace import Trace, TraceGraph # noqa: F401
+
############################################
# Begin primitive operations
