// from: https://en.wikipedia.org/w/index.php?title=YANG&oldid=792171830#Example
module example-sports {

namespace "http://example.com/example-sports";
prefix sports;

import ietf-yang-types { prefix yang; }

typedef season {
type string;
description
"The name of a sports season, including the type and the year, e.g,
'Champions League 2014/2015'.";
}

container sports {
config true;

list person {
key name;
leaf name { type string; }
leaf birthday { type yang:date-and-time; mandatory true; }
}

list team {
key name;
leaf name { type string; }
list player {
key "name season";
unique number;
leaf name { type leafref { path "/sports/person/name"; } }
leaf season { type season; }
leaf number { type uint16; mandatory true; }
leaf scores { type uint16; default 0; }
}
}
}
}