from datafusion import SessionContext
from datafusion.expr import Filter


def traverse_logical_plan(plan):
    cur_node = plan.to_variant()
    if isinstance(cur_node, Filter):
        predicate = cur_node.predicate().to_variant()
    if hasattr(plan, 'inputs'):
        for input_plan in plan.inputs():
            traverse_logical_plan(input_plan)


if __name__ == "__main__":
    ctx = SessionContext()
    data = {'id': [1, 2, 3], 'name': ['Alice', 'Bob', 'Charlie']}
    ctx.from_pydict(data, name='table1')
    query = "SELECT * FROM table1 t1 WHERE t1.name IN ('dfa', 'ad', 'dfre', 'vsa')"
    logical_plan = ctx.sql(query).optimized_logical_plan()
    traverse_logical_plan(logical_plan)

  File "minimal_example.py", line 8, in traverse_logical_plan
    predicate = cur_node.predicate().to_variant()
RuntimeError: "Cannot convert this Expr to a Python object: InList(InList { expr: Column(Column { relation: Some(Bare { table: \"table1\" }), name: \"name\" }), list: [Literal(Utf8(\"dfa\")), Literal(Utf8(\"ad\")), Literal(Utf8(\"dfre\")), Literal(Utf8(\"vsa\"))], negated: false })"