code change based on review

Author: charlesdong1991

pandas/plotting/_core.py

@@ -308,11 +308,10 @@ def _setup_subplots(self):
 
         axes = _flatten(axes)
 
-        valid_log = (False, True, 'sym', None)
-
-        for i in (self.logx, self.logy, self.loglog):
-            if i not in valid_log:
-                raise ValueError("Valid inputs are boolean, None and 'sym'.")
+        valid_log = {False, True, 'sym', None}
+        input_log = {self.logx, self.logy, self.loglog}
+        if input_log - valid_log:
+            raise ValueError("Valid inputs are boolean, None and 'sym'.")
 
         if self.logx is True or self.loglog is True:
             [a.set_xscale('log') for a in axes]

pandas/tests/plotting/test_frame.py

@@ -259,12 +259,13 @@ def test_logscales(self):
         assert ax.get_yscale() == 'symlog'
 
     @pytest.mark.parametrize("wrong_input", ["sm", "symlog"])
-    def test_invalid_logscale(self, wrong_input):
+    @pytest.mark.parametrize("input_param", ["logx", "logy", "loglog"])
+    def test_invalid_logscale(self, wrong_input, input_param):
         df = DataFrame({'a': np.arange(100)}, index=np.arange(100))
 
         msg = "Valid inputs are boolean, None and 'sym'."
         with pytest.raises(ValueError, match=msg):
-            df.plot(logy=wrong_input)
+            df.plot(**{input_param: wrong_input})
 
     @pytest.mark.slow
     def test_xcompat(self):