code: def test_small_samples_binary(self):
      X = np.array(["a", "b", "b"])
      y = np.array([1, 0, 1])
      out = encoders.JamesSteinEncoder(
          return_df=False, model="binary"
      ).fit_transform(X, y)
      self.assertTrue(
          np.sum(
              np.abs(
                  [
                      np.log((1.5 * 1.5) / (0.5 * 1.5)),
                      np.log((0.5 * 1.5) / (1.5 * 1.5)),
                      np.log((0.5 * 1.5) / (1.5 * 1.5)),
                  ]
                  - np.transpose(out)
              )
          )
          < 0.001,
          "When the count of unique values in the column is <4 (here it is 2), James-Stein estimator returns (unbiased) sample means",
      )
  
imports: from unittest import TestCase
  import numpy
  import category_encoders
label_desc: Use image node_id 13 for calling the TestJamesSteinEncoder obj's underlying member method code with example usage: obj.test_small_samples_binary() without return types