esg issuer graph
Note : As description about decision of cyclic and noncyclic was missing So I have not written the code for that as it will be completely part of assumptions and it will may lead to the incorrect solution.

I have written code for finding the issuer with max rating.

Drop a comment if you need further help I will be happy to help you.

Thanks..!!

Code:-

ratings = {}
esg issuer graph How to get it? esg issuer graph

ratings['AAA']=9
ratings['AA']=8
ratings['A']=7
ratings['BBB']=6
ratings['BB']=5
ratings['B']=4
ratings['CCC']=3
ratings['CC']=2
ratings['C']=1
esg issuer graph How to use it? esg issuer graph

issuer = []
parent = []
rating = []

maxRating = 0
maxIssuer = ''
maxRatingText = ''

#reading a file
esg issuer graph How to get it for free? esg issuer graph
file = open('input.txt','r')

for line in file:
    data = line.split('|')
    issuer.append(data[0])
    parent.append(data[1])
    rating.append(data[2].replace('\n',''))
    
#loop to find max
for i in range(len(issuer)):
esg issuer graph How to get it for free? esg issuer graph
    if(ratings[rating[i]] > maxRating):
        maxRating = ratings[rating[i]]
        maxRatingText = rating[i]
        maxIssuer = issuer[i]

print(maxIssuer)
print(maxRatingText)

Output:-
https://ibb.co/qmVmdmt
esg issuer graph How to get it for free? esg issuer graph
esg issuer graph