def groupby$($data:list, key:callable$)$:

$\text{'}\text{'}\text{'}$

Given a list of items, and a key, create a dictionary with the key as key function called

on item and the list of items with the same key as the corresponding value.

The order of items in the group should be the same order in the original list

$\text{'}\text{'}\text{'}$

$...$

def apply$\_$to$\_$groups$($groups:dict, func:callable$)$:

$\text{'}\text{'}\text{'}$

Apply a function to the list of items for each group.

$\text{'}\text{'}\text{'}$

$...$

def min$\_$course$\_$marks$($student$\_$data, course$)$:

$\text{'}\text{'}\text{'}$Return the min marks on a given course'$\text{'}\text{'}$

$...$

def max$\_$course$\_$marks$($student$\_$data, course$)$:

$\text{'}\text{'}\text{'}$Return the max marks on a given course'$\text{'}\text{'}$

$...$

def rollno$\_$of$\_$max$\_$marks$($student$\_$data, course$)$:

$\text{'}\text{'}\text{'}$Return the rollno of student with max marks in a course'$\text{'}\text{'}$

$...$

def sort$\_$rollno$\_$by$\_$marks$($student$\_$data, course$1,$ course$2,$ course$3)$:

$\text{'}\text{'}\text{'}$

Return a sorted list of rollno sorted based on their marks on the three course marks.

course$1$ is compared first, then course$2,$ then course$3$ to break ties.

Hint: use tuples comparision

$\text{'}\text{'}\text{'}$

$...$

def count$\_$students$\_$by$\_$cities$($student$\_$data$)$:

$\text{'}\text{'}\text{'}$

Create a dictionary with city as key and number of students from each city as value.

$\text{'}\text{'}\text{'}$

$...$

def city$\_$with$\_$max$\_$no$\_$of$\_$students$($student$\_$data$)$:

$\text{'}\text{'}\text{'}$

Find the city with the maximum number of students.

$\text{'}\text{'}\text{'}$

$...$

def group$\_$rollnos$\_$by$\_$cities$($student$\_$data$)$:

$\text{'}\text{'}\text{'}$

Create a dictionary with city as key and

a sorted list of rollno of students that belong to

that city as the value.

$\text{'}\text{'}\text{'}$

$...$

def city$\_$with$\_$max$\_$avg$\_$course$\_$mark$($student$\_$data, course$)$:

$\text{'}\text{'}\text{'}$

Find the city with the maximum avg course marks.

$\text{'}\text{'}\text{'}$

$...$