Fix mypy errors

miplearn/extractors/AlvLouWeh2017.py

@@ -22,7 +22,7 @@ class AlvLouWeh2017Extractor(FeaturesExtractor):
         self.with_m3 = with_m3
 
     def get_instance_features(self, h5: H5File) -> np.ndarray:
-        raise NotImplemented()
+        raise NotImplementedError()
 
     def get_var_features(self, h5: H5File) -> np.ndarray:
         """
@@ -197,7 +197,7 @@ class AlvLouWeh2017Extractor(FeaturesExtractor):
         return features
 
     def get_constr_features(self, h5: H5File) -> np.ndarray:
-        raise NotImplemented()
+        raise NotImplementedError()
 
 
 def _fix_infinity(m: Optional[np.ndarray]) -> None:

miplearn/extractors/fields.py

@@ -31,9 +31,9 @@ class H5FieldsExtractor(FeaturesExtractor):
                 data = h5.get_scalar(field)
             assert data is not None
             x.append(data)
-        x = np.hstack(x)
-        assert len(x.shape) == 1
-        return x
+        x_np = np.hstack(x)
+        assert len(x_np.shape) == 1
+        return x_np
 
     def get_var_features(self, h5: H5File) -> np.ndarray:
         var_types = h5.get_array("static_var_types")
@@ -51,13 +51,14 @@ class H5FieldsExtractor(FeaturesExtractor):
             raise Exception("No constr fields provided")
         return self._extract(h5, self.constr_fields, n_constr)
 
-    def _extract(self, h5, fields, n_expected):
+    def _extract(self, h5: H5File, fields: List[str], n_expected: int) -> np.ndarray:
         x = []
         for field in fields:
             try:
                 data = h5.get_array(field)
             except ValueError:
                 v = h5.get_scalar(field)
+                assert v is not None
                 data = np.repeat(v, n_expected)
             assert data is not None
             assert len(data.shape) == 1