code: def df_enc_rare():
      df = {
          "var_A": ["B"] * 9 + ["A"] * 6 + ["C"] * 4 + ["D"] * 1,
          "var_B": ["A"] * 10 + ["B"] * 6 + ["C"] * 4,
          "target": [
              1,
              1,
              0,
              0,
              0,
              0,
              0,
              0,
              0,
              0,
              1,
              1,
              0,
              0,
              0,
              0,
              1,
              1,
              0,
              0,
          ],
      }
      df = pd.DataFrame(df)
  
      return df
  
file_path: feature_engine/tests/conftest.py
imports: import numpy
  import pandas
  import pytest
label_desc: Use image node_id 8 for calling a global function with example usage: df_enc_rare() and returns: df