code: def test_len(data):
      gsr = cudf.Series(data)
      psr = gsr.to_pandas()
  
      expect = psr.map(lambda x: len(x) if x is not None else None)
      got = gsr.list.len()
  
      assert_eq(expect, got, check_dtype=False)
  
imports: import functools
  import operator
  import numpy
  import pandas
  import pyarrow
  import pytest
  import cudf
  from cudf import NA
  from cudf._lib.copying import get_element
  from cudf.api.types import is_scalar
  from cudf.testing._utils import DATETIME_TYPES, NUMERIC_TYPES, TIMEDELTA_TYPES, assert_eq
label_desc: Use image node_id 10 for calling a global function with example usage: test_len(data) without return types