Provide PHP code to create a learner grade calculator program with following specifications

$-$In the calculator program, define learner class with name and

grades, functions to calculate the average and determine letter grade based on the

average, and a loop to process multiple leaners with user input for their grades.

Class: learner

Define a class named leaner with

$-$name $($string$)-$leaners name,

$-$grades $($array$)-$ Array containing leaner grades $($integers$)$

Implement a constructor method that takes the student's name and an array of

grades as arguments and initialises the corresponding properties.

Function: calculateAverage:

$$ Create a function named calculateAverage that takes a learner object as

an argument.

$$ Inside the function, loop through the student's grades array and calculate

the average grade.

$$ The function should return the calculated average grade $($float$).$

Develop a function named determineLetterGrade that takes a float $($average

grade$)$ as an argument.

$$ Implement a logic to determine the letter grade based on the average using

a switch statement or if$-$else statements. Here's a sample grading scale:

a$.$ A: $90-100$

b$.$ B: $80-89$

c$.$ C: $70-79$

d$.$ D: $60-69$

e$.$ F: Below $60$

$$ The function should return the corresponding letter grade $($string$).$

Within the main PHP file:

$$ Create an array of learner names.

$$ Loop through the learner names array.

$$ For each leaner, prompt the user to enter their grades $($integers$)$ one by

one using a loop. Store these grades in an array

$$ Create a new learner object by passing the learner's name and their grade

array to the constructor.

$$ Call the calculateAverage function with the learner object as an argument

and store the returned average.

$$ Call the determineLetterGrade function with the calculated average and

store the returned letter grade.

$$ then, display the learner's name, average grade, and letter grade in a

user$-$friendly format $($e$.$g$.,$ "Student Name: Mary Jane, Average: $68\mathrm{.}5,$ Letter

Grade: B$").$