Last caracter of a string truncated issue when working from the end of the string

[Yoriz]

Rather than [-7:-1] to go to the end [-7:] -7 and the rest.

dst = (r"C:\Users\tekno\Documents\Client Drawings\AAA001")
dwg_name = dst[-7:]
print(dst)
print(dwg_name)

Output:
C:\Users\tekno\Documents\Client Drawings\AAA001
\AAA001