code: def test_data_frame_value_counts_single_col_default():
      df = pd.DataFrame({"num_legs": [2, 4, 4, 6]})
  
      result = df.value_counts()
      expected = pd.Series(
          data=[2, 1, 1],
          index=pd.MultiIndex.from_arrays(
              [[4, 2, 6]], names=["num_legs"]
          ),
          name="count",
      )
  
      tm.assert_series_equal(result, expected)
  
file_path: pandas/pandas/tests/frame/methods/test_value_counts.py
imports: import numpy
  import pytest
  import pandas
  import pandas._testing
label_desc: Use image node_id 5 for calling a global function with example usage: test_data_frame_value_counts_single_col_default() without return types