import re

print(re.findall(r"([A-Z]\[[A-Z]\]\[[a-z]\])([A-Z]\[[a-z]+\])?", "A[B][q]G[boy]"))
print(re.findall(r"([A-Z]\[[A-Z]\]\[[a-z]\])([A-Z]\[[a-z]+\])?", "A[B][q]"))