updated for version 7.3.288
Problem:    has('python') may give an error message for not being able to load
            the library after using python3.
Solution:   Only give the error when the verbose argument is true.
diff --git a/src/if_python3.c b/src/if_python3.c
index 023a773..644cf18 100644
--- a/src/if_python3.c
+++ b/src/if_python3.c
@@ -367,7 +367,8 @@
      * standard C extension libraries of one or both python versions. */
     if (python_loaded())
     {
-	EMSG(_("E837: This Vim cannot execute :py3 after using :python"));
+	if (verbose)
+	    EMSG(_("E837: This Vim cannot execute :py3 after using :python"));
 	return FAIL;
     }
 # endif