Function validate_flange 

pub fn validate_flange(flange: &str) -> bool

Validate if flange is either u v o or h other values are not allowed

arguments

• flange - flange code

return

• bool - true if flange is valid

example

use dstv::validate_flange;
assert_eq!(validate_flange("u"), true);
assert_eq!(validate_flange("v"), true);
assert_eq!(validate_flange("o"), true);
assert_eq!(validate_flange("h"), true);
assert_eq!(validate_flange("x"), false);