string = "varun"
# arg1 is letter to be searched
# arg2 is starting index
# arg3 is end index
string.find("r", 0, 4)
# OUTPUT --> 2
def find_all_indexes(input_str, search_str):
l1 = []
length = len(input_str)
index = 0
while index < length:
i = input_str.find(search_str, index)
if i == -1:
return l1
l1.append(i)
index = i + 1
return l1
s = 'abaacdaa12aa2'
print(find_all_indexes(s, 'a'))
print(find_all_indexes(s, 'aa'))