// 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; }
      }
    }
  }
}