How to get everything between two characters?

Example:

string = "aabcdefgg"
string.inbetween("a", "g") # abcdefg

I want to avoid regex, if possible.

Edit:
I want to get the characters in between the first occurrence of both arguments.

>Solution :

What about a simple find?

string = "aabcdefgg"
start = string.find("a") + 1
end = string.find("g", start) + 1
print(string[start:end])  # abcdefg