improve on following code

Create a Student class that encapsulates attributes and methods related to individual student records.

class Student:

def $\_\_$init$\_\_($self$,$ id$,$ name, grades$)$:

self.id $=$ id

self.name $=$ name

self.grades $=$ grades

def average$\_$grade$($self$)$:

return sum$($self$.$grades$)/$ len$($self$.$grades$)$

def $\_\_$str$\_\_($self$)$:

return f$"$Student$($ID: $\{$self$.$id$\},$ Name: $\{$self$.$name$\},$ Grades: $\{$self$.$grades$\})"$

Design a DatasetManager class to handle loading, preprocessing, and transforming the dataset.

import pandas as pd

class DatasetManager:

def $\_\_$init$\_\_($self$,$ url$)$:

self.url $=$ url

self.data $=$ None

def load$\_$data$($self$)$:

self.data $=$ pd$.$read$\_$csv$($self$.$url, sep$=\text{'}$;$\text{'})$

return self.data

def preprocess$\_$data$($self$)$:

self.data.fillna$($method$=$'ffill', inplace$=$True$)$

self.data $=$ pd$.$get$\_$dummies$($self$.$data$)$

return self.data

def get$\_$students$($self$)$:

students $=[]$

for idx, row in self.data.iterrows$()$:

student $=$ Student$($

id$=$row$[\text{'}$ID$\text{'}],$

name$=$row$[\text{'}$Name$\text{'}],$

grades$=[$row$[\text{'}$G$1\text{'}],$ row$[\text{'}$G$2\text{'}],$ row$[\text{'}$G$3\text{'}]]$

$)$

students.append$($student$)$

return students

Develop subclasses that inherit from a base class, implementing specialized methods for different types of analysis $($e$.$g$.,$ GradeAnalysis subclass for analyzing grades$).$

class AnalysisBase:

def $\_\_$init$\_\_($self$,$ students$)$:

self.students $=$ students

def analyze$($self$)$:

raise NotImplementedError$("$Subclasses should implement this!"$)$

class GradeAnalysis$($AnalysisBase$)$:

def analyze$($self$)$:

for student in self.students:

print$($f$"\{$student$.$name$\}\text{'}$s average grade: $\{$student$.$average$\_$grade$()\}")$

Demonstrate polymorphism by overriding methods in subclasses to provide specific functionalities

class AttendanceAnalysis$($AnalysisBase$)$:

def analyze$($self$)$:

for student in self.students:

# Example placeholder analysis

print$($f$"\{$student$.$name$\}$ has perfect attendance."$)$

Utilize class methods and properties to interact with the data, ensuring data integrity and encapsulation.

class Student:

def $\_\_$init$\_\_($self$,$ id$,$ name, grades$)$:

self.id $=$ id

self.name $=$ name

self.grades $=$ grades

@property

def average$\_$grade$($self$)$:

return sum$($self$.$grades$)/$ len$($self$.$grades$)$

def $\_\_$str$\_\_($self$)$:

return f$"$Student$($ID: $\{$self$.$id$\},$ Name: $\{$self$.$name$\},$ Grades: $\{$self$.$grades$\})"$

Optionally integrate Pandas or NumPy methods within class methods to manipulate data frames or arrays if these libraries are used.

class GradeAnalysis$($AnalysisBase$)$:

def analyze$($self$)$:

grades$\_$df $=$ pd$.$DataFrame$([$student$.$grades for student in self.students$],$ columns$=[\text{'}$G$1\text{'},\text{'}$G$2\text{'},\text{'}$G$3\text{'}])$

print$("$Average Grades by Exam:"$)$

print$($grades$\_$df$.$mean$())$