code: def test_ratio_error_if_denominator_probability_zero():
      # test case 3: when the denominator probability is zero, ratio
      with pytest.raises(ValueError):
          df = {
              "var_A": ["A"] * 6 + ["B"] * 10 + ["C"] * 4,
              "var_B": ["A"] * 10 + ["B"] * 6 + ["C"] * 4,
              "target": [
                  1,
                  1,
                  1,
                  1,
                  1,
                  1,
                  0,
                  0,
                  0,
                  0,
                  1,
                  1,
                  0,
                  0,
                  0,
                  0,
                  1,
                  1,
                  0,
                  0,
              ],
          }
          df = pd.DataFrame(df)
          encoder = PRatioEncoder(encoding_method="ratio")
          encoder.fit(df[["var_A", "var_B"]], df["target"])
  
file_path: feature_engine/tests/test_encoding/test_probability_ratio_encoder.py
imports: import pandas
  import pytest
  from feature_engine.encoding import PRatioEncoder
label_desc: Use image node_id 3 for calling a global function with example usage: test_ratio_error_if_denominator_probability_zero() without return types