documented DataFrame.merge behaviour for suffix=(False, False)

Author: elmq0022

pandas/core/frame.py

@@ -183,7 +183,8 @@
     the order of the join keys depends on the join type (how keyword).
 suffixes : 2-length sequence (tuple, list, ...)
     Suffix to apply to overlapping column names in the left and right
-    side, respectively.
+    side, respectively. If (False, False), overlapping
+    column names raise an error.
 copy : boolean, default True
     If False, avoid copy if possible.
 indicator : boolean or string, default False