Fixed flake differences, Added tag in docs

Author: jeffcarey

doc/source/io.rst

@@ -2824,6 +2824,8 @@ argument to ``to_excel`` and to ``ExcelWriter``. The built-in engines are:
 
    df.to_excel('path_to_file.xlsx', sheet_name='Sheet1')
 
+.. _io.excel.style:
+
 Style and Formatting
 ''''''''''''''''''''
 

pandas/core/frame.py

@@ -1417,12 +1417,13 @@ def to_excel(self, excel_writer, sheet_name='Sheet1', na_rep='',
             excel_writer.save()
 
     def _validate_freeze_panes(self, freeze_panes):
-        if freeze_panes is not None: 
-            if (len(freeze_panes) == 2 and
+        if freeze_panes is not None:
+            if (
+                len(freeze_panes) == 2 and
                 all(isinstance(item, int) for item in freeze_panes)
             ):
                 return freeze_panes
-            else:
+
                 raise ValueError("freeze_panes must be of form (row, column)"
                                  " where row and column are integers")
 

pandas/io/tests/test_excel.py

@@ -1836,12 +1836,11 @@ def test_true_and_false_value_options(self):
                                     false_values=['bar'])
             tm.assert_frame_equal(read_frame, expected)
 
-
-    # GH15160
     def test_freeze_panes(self):
-        expected = DataFrame([[1, 2], [3,4]], columns=['col1', 'col2'])
+        # GH15160
+        expected = DataFrame([[1, 2], [3, 4]], columns=['col1', 'col2'])
         with ensure_clean(self.ext) as path:
-            expected.to_excel(path, "Sheet1", freeze_panes=(1,1))
+            expected.to_excel(path, "Sheet1", freeze_panes=(1, 1))
             result = read_excel(path)
             tm.assert_frame_equal(expected, result)