code: function ( qu, value ) {
  		var operands;
  
  		operands = sys.flatten( qu.operands );
  		return sys.indexOf( operands, value ) > -1;
  	}
docs: `$in` Sees if a field has one of the values in the query
  `{field: {$in: [test1, test2, test3,...]}}`
  @name $in
  @memberOf module:documents/probe.queryOperators
  @example
  var probe = require("documents/probe");
  probe.find( data, {"age" : {$in : [24, 28, 60]}} );