code: def test_from_pandas_ex1():
      pdf = pd.DataFrame(
          {"a": [0, 1, 2, 3], "b": [0.1, 0.2, None, 0.3]}
      )
      df = DataFrame.from_pandas(pdf)
  
      assert tuple(df.columns) == tuple(pdf.columns)
      assert np.all(df["a"].to_numpy() == pdf["a"])
      matches = df["b"].to_numpy(na_value=np.nan) == pdf["b"]
      # the 3d element is False due to (nan == nan) == False
      assert np.all(matches == [True, True, False, True])
      assert np.isnan(df["b"].to_numpy(na_value=np.nan)[2])
      assert np.isnan(pdf["b"][2])
  
file_path: cudf/python/cudf/cudf/tests/test_pandas_interop.py
imports: import numpy
  import pandas
  import cudf
  from cudf import DataFrame
  from cudf.testing._utils import assert_eq
label_desc: Use image node_id 3 for calling a global function with example usage: test_from_pandas_ex1() without return types