Match ‘a’ followed by 3 chars

pattern = ‘a{3}?’

Write a python program that matches a string
that has an a followed by three ‘b’.
import re

def text_match(S):

    pattern = 'a{3}?'

    if re.search(pattern,  S):
        return 'Found a match!'
    else:
        return('Not matched!')

# test
print(text_match("abbb"))       # Found a match!
print(text_match("aabbbbbc"))   # Found a match!