Update comments and parenthesis for if condition

Author: fleimgruber

pandas/core/indexing.py

@@ -2734,8 +2734,8 @@ def _non_reducing_slice(slice_):
     def pred(part):
         # true when slice does *not* reduce, False when part is a tuple,
         # i.e. MultiIndex slice
-        return (isinstance(part, slice) or is_list_like(part))\
-            and not isinstance(part, tuple)
+        return ((isinstance(part, slice) or is_list_like(part))
+                and not isinstance(part, tuple))
 
     if not is_list_like(slice_):
         if not isinstance(slice_, slice):

pandas/tests/indexing/test_indexing.py

@@ -813,6 +813,7 @@ def test_non_reducing_slice(self):
             assert isinstance(df.loc[tslice_], DataFrame)
 
     def test_non_reducing_slice_on_multiindex(self):
+        # GH 19861
         dic = {
             ('a', 'd'): [1, 4],
             ('a', 'c'): [2, 3],

pandas/tests/io/formats/test_style.py

@@ -275,7 +275,8 @@ def f(x):
             assert result == expected
 
     def test_applymap_subset_multiindex(self):
-        # https://github.com/pandas-dev/pandas/issues/19861
+        # GH 19861
+        # Smoke test for applymap
         def color_negative_red(val):
             """
             Takes a scalar and returns a string with