**English**

Okay, I guess we have to turn to plan B.

What's plan B?

Why wasn't that plan A?- The Big Band Theory : "The Lizard-Spock Expansion"

doveryai no proveryai (trust, but verify)- Russian proverb adopted as signature phrase by Ronald Reagan

Two functions *f* and *g* are provided as inputs to *checkio*. The first function *f* is
the primary function and the second function *g* is the backup. Use your coding skills to return a third function
*h* which returns the same output as *f* unless *f* raises an exception or returns *None*.
In this case *h* should return the same output as *g*. If both *f* and *g* raise exceptions
or return *None*, then *h* should return *None*.

As a second output, *h* should return a status string indicating whether the function values are the same and
if either function erred. A function errs if it raises an exception or returns a null value (*None*).

The status string should be set to: "same" if *f* and *g* return the same output and neither errs,
"different" if *f* and *g* return different outputs and neither errs, "f_error" if *f* errs
but not *g*, "g_error" if *g* errs but not *f*, or "both_error" if both err.

**Input: ** Two functions: f (primary) and g (backup).

**Output: ** A function h which takes arbitrary inputs and returns a two-tuple.

**Example:**

f = lambda x,y: x+y g = lambda x,y: (x**2 - y**2)/(x-y) checkio(f,g)(1,3) == (4,"same") checkio(f,g)(1,1.01) == (2.01,"different") # numerical precision difference checkio(f,g)(1,1) == (2,"g_error") # g divides by zero

**How it is used: **
This is an exercise in working with functions as first class objects.

**Precondition:**
hasattr(f,'__call__');

hasattr(g,'__call__')