Add input check to secondary axes

ZachDaChampion · ZachDaChampion · commit ae7bc50c0545 · 2023-04-14T23:39:16.000-04:00
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -597,6 +597,14 @@ def invert(x):
         if not (location in ['top', 'bottom'] or isinstance(location, Real)):
             raise ValueError('secondary_xaxis location must be either '
                              'a float or "top"/"bottom"')
+        if not (isinstance(transform, mtransforms.Transform) or transform is None):
+            raise ValueError('transform must be either an mtransforms.Transform '
+                             'or None')
+
+        secondary_ax = SecondaryAxis(self, 'x', location, functions,
+                                        transform, **kwargs)
+        self.add_child_axes(secondary_ax)
+        return secondary_ax
 
         secondary_ax = SecondaryAxis(self, 'x', location, functions,
                                      transform, **kwargs)
@@ -641,6 +649,13 @@ def secondary_yaxis(self, location, *, functions=None, transform=None, **kwargs)
         if not (location in ['left', 'right'] or isinstance(location, Real)):
             raise ValueError('secondary_xaxis location must be either '
                              'a float or "left"/"right"')
+        if not (isinstance(transform, mtransforms.Transform) or transform is None):
+            raise ValueError('transform must be either an mtransforms.Transform '
+                             'or None')
+        secondary_ax = SecondaryAxis(self, 'y', location, functions,
+                                        transform, **kwargs)
+        self.add_child_axes(secondary_ax)
+        return secondary_ax
 
         secondary_ax = SecondaryAxis(self, 'y', location, functions,
                                      transform, **kwargs)
