code: def test_expression_json() -> None:
      e = pl.col("foo").sum().over("bar")
      json = e.meta.write_json()
  
      round_tripped = pl.Expr.from_json(json)
      assert round_tripped.meta == e
  
imports: from __future__ import annotations
  import io
  import pickle
  from datetime import datetime, timedelta
  import pytest
  import polars
  from polars import StringCache
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 10 for calling a global function with example usage: test_expression_json() without return types