Syntax

# Write your max_key function here:
def max_key(my_dictionary):
  largest_key = float("-inf")
  largest_value = float("-inf")
  for key, value in my_dictionary.items():
    if value > largest_value:
      largest_value = value
      largest_key = key
  return largest_key

can anyone please explain this code

What part about it is confusing? Is it the float("-inf") part or the whole function?

Break it down into smaller pieces and talk it out.

A dictionary in python is comprised of {key: value, key: value}

You’re writing a function where you want to return the largest key in a dictionary.

First, what does this part do?

largest_key = float("-inf")
 largest_value = float("-inf")

This might be of some help. If all else fails use Google:
https://stackoverflow.com/questions/34264710/what-is-the-point-of-floatinf-in-python

And this:
https://www.geeksforgeeks.org/python-infinity/

Then ask yourself, what does this for loop do? What does the .items() method do with a dictionary?

for key, value in my_dictionary.items():

May be you don’t undertand what
largest_key = float("-inf")
exactly means. You can think about that this way:
For each number n you can choose is True:

float("-inf") < n.

So in this way of thinking largest_key = float("-inf") is initialization of sorting exactly the same way we initialize summarize with sum = 0, or multiplication with mult = 1.