Help me in solving PYTH99A problem

My issue

My code

# Count how many 'o's are present in the string using a 'for' loop and 'if' condition

string = 'bolloon'

# use this variable to count occurrences of o
count_o = 0      

for i in string:
    "if i == 'o':"
"count_o by 1"   
       # count_o = count_o + 1

Learning course: Learn Python
Problem Link: CodeChef: Practical coding for everyone