fix errors

Author: topper-123

pandas/core/indexes/category.py

@@ -286,6 +286,7 @@ def astype(self, dtype, copy: bool = True) -> Index:
 
         cat = self.categories
         if type(cat) is NumIndex:
+            assert isinstance(cat, NumIndex)  # mypy complaint fix
             try:
                 cat._validate_dtype(dtype)
             except ValueError:

pandas/tests/base/test_unique.py

@@ -24,7 +24,7 @@ def test_unique(index_or_series_obj):
         expected = pd.MultiIndex.from_tuples(unique_values)
         expected.names = obj.names
         tm.assert_index_equal(result, expected)
-    elif isinstance(obj, pd.NumIndex):
+    elif type(obj) is pd.NumIndex:
         expected = pd.NumIndex(unique_values, dtype=obj.dtype)
         tm.assert_index_equal(result, expected)
     elif isinstance(obj, pd.Index):
@@ -65,7 +65,7 @@ def test_unique_null(null_obj, index_or_series_obj):
     unique_values_not_null = [val for val in unique_values_raw if not pd.isnull(val)]
     unique_values = [null_obj] + unique_values_not_null
 
-    if isinstance(obj, pd.NumIndex):
+    if type(obj) is pd.NumIndex:
         expected = pd.NumIndex(unique_values, dtype=obj.dtype)
         tm.assert_index_equal(result, expected)
     elif isinstance(obj, pd.Index):