Will you please help me to code the question below using Python language? Please include comments on the code too. Thanks

Create a program encodes a text file (please refer to the screenshot, because I don't know how to attach a file here) using a caesar cipher. It should take as input a shift value from 1-26 and the name of a text file, and write the encoded text to output fileciphertext.txt.To encode the file, add the shift value to the unicode value for each character, INCLUDING punctuation and whitespace. You are not required to decode the ciphertext version, but it does help for testing purposes.

Excerpt.txt

I live in the oldest city in the world. Long before there were kings in

Karhide, Rer was a city, the marketplace and meeting ground for all the

Northeast, the Plains, and Kerm Land. The Fastness of Rer was a center of

learning, a refuge, a judgment seat fifteen thousand years ago. Karhide

became a nation here, under the Geger kings, who ruled for a thousand

years. In the thousandth year Sedern Geger, the Unking, cast the crown

into the River Arre from the palace towers, proclaiming an end to

dominion. The time they call the Flowering of Rer, the Summer Century,

began then. It ended when the Hearth of Harge took power and moved their

capital across the mountains to Erhenrang. The Old Palace has been empty

for centuries. But it stands. Nothing in Rer falls down. The Arre floods

through the street-tunnels every year in the Thaw, winter blizzards may

bring thirty feet of snow, but the city stands. Nobody knows how old the

houses are, because they have been rebuilt forever. Each one sits in its

gardens without respect to the position of any of the others, as vast and

random and ancient as hills. The roofed streets and canals angle about

among them. Rer is all corners. We say that the Harges left because they

were afraid of what might be around the corner.

I live in the oldest city in the world. Long before there were kings in

Karhide, Rer was a city, the marketplace and meeting ground for all the

Northeast, the Plains, and Kerm Land. The Fastness of Rer was a center of

learning, a refuge, a judgment seat fifteen thousand years ago. Karhide

became a nation here, under the Geger kings, who ruled for a thousand

years. In the thousandth year Sedern Geger, the Unking, cast the crown

into the River Arre from the palace towers, proclaiming an end to

dominion. The time they call the Flowering of Rer, the Summer Century,

began then. It ended when the Hearth of Harge took power and moved their

capital across the mountains to Erhenrang. The Old Palace has been empty

for centuries. But it stands. Nothing in Rer falls down. The Arre floods

through the street-tunnels every year in the Thaw, winter blizzards may

bring thirty feet of snow, but the city stands. Nobody knows how old the

houses are, because they have been rebuilt forever. Each one sits in its

gardens without respect to the position of any of the others, as vast and

random and ancient as hills. The roofed streets and canals angle about

among them. Rer is all corners. We say that the Harges left because they

were afraid of what might be around the corner.

I live in the oldest city in the world. Long before there were kings irn Karhide, Rer was a city, the marketplace and meeting ground for all the Northeast, the Plains, and Kerm Land. The Fastness of Rer was a center of learning, a refuge, a judgment seat fifteen thousand years ago. Karhide became a nation here, under the Geger kings, who ruled for a thousand years. In the thousandth year Sedern Geger, the Unking, cast the crown into the River Arre from the palace towers, proclaiming an end to dominion. The time they call the Flowering of Rer, the Summer Century, began then. It ended when the Hearth of Harge took power and moved their capital across the mountains to Erhenrang. The Old Palace has been empty for centuries. But it stands. Nothing in Rer falls down. The Arre floods through the street-tunnels every year in the Thaw, winter blizzards may bring thirty feet of snow, but the city stands. Nobody knows how old the houses are, because they have been rebuilt forever. Each one sits in its gardens without respect to the position of any of the others, as vast and random and ancient as hills. The roofed streets and canals angle about among them. Rer is all corners. We say that the Harges left because they were afraid of what might be arund the corner