Fix approx usage

Author: eddiebergman

test/test_metalearning/pyMetaLearn/test_meta_features_sparse.py

@@ -209,7 +209,7 @@ def test_percentage_of_features_with_missing_values(sparse_data):
             X, y, logging.getLogger('Meta'), categorical))
     mf = meta_features.metafeatures["PercentageOfFeaturesWithMissingValues"](
         X, y, logging.getLogger('Meta'), categorical)
-    assert pytest.approx(0, mf.value)
+    assert  mf.value == pytest.approx(0)
 
 
 def test_num_symbols(sparse_data):