code: def test_expand_column():
      data = {
          "col1": ["A, B", "B, C, D", "E, F", "A, E, F"],
          "col2": [1, 2, 3, 4],
      }
  
      df = pd.DataFrame(data)
      expanded_df = df.expand_column(
          column_name="col1", sep=", ", concat=False
      )
      assert expanded_df.shape[1] == 6
  
imports: import pandas
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: test_expand_column() without return types