ENH: Check that v is not a callable (#13473)

In this commit, the bug is removed from the code, which raised a
TypeError if a function was passed to rename instead of a dictionary.

Author: MaxVanDeursen

Diff for: pandas/core/generic.py

@@ -1098,11 +1098,13 @@ def rename(self, *args, **kwargs):
                 level = self.axes[axis]._get_level_number(level)
 
             # GH 13473
-            indexer = self.axes[axis].get_indexer_for(v)
-            missing_labels = [label for index, label in enumerate(v)
-                              if indexer[index] == -1]
-            if errors == 'raise' and len(missing_labels) > 0:
-                raise KeyError('{} not found in axis'.format(missing_labels))
+            if not callable(v):
+                indexer = self.axes[axis].get_indexer_for(v)
+                missing_labels = [label for index, label in enumerate(v)
+                                  if indexer[index] == -1]
+                if errors == 'raise' and len(missing_labels) > 0:
+                    raise KeyError('{} not found in axis'
+                                   .format(missing_labels))
 
             result._data = result._data.rename_axis(f, axis=baxis, copy=copy,
                                                     level=level)

Diff for: pandas/tests/frame/test_alter_axes.py

@@ -890,6 +890,10 @@ def test_rename_errors(self):
         expected = DataFrame(columns=['a', 'B', 'C', 'D'])
         tm.assert_frame_equal(renamed, expected)
 
+        renamed = df.rename(columns=str.lower, errors='raise')
+        expected = DataFrame(columns=['a', 'b', 'c', 'd'])
+        tm.assert_frame_equal(renamed, expected)
+
     def test_reorder_levels(self):
         index = MultiIndex(levels=[['bar'], ['one', 'two', 'three'], [0, 1]],
                            codes=[[0, 0, 0, 0, 0, 0],