use decode_jwt;
/**
* This function retrieves the expiration time from a JWT token.
* It takes a JWT token as input and returns the expiration time in seconds.
* If the decoding fails, it returns None.
* # Arguments
* * `jwt` - A string slice that holds the JWT token to be decoded.
* # Returns
* * `Option<usize>` - An optional value that contains the expiration time in seconds if successful,
* or None if decoding fails.
*/