{
"sets" : [
{
"quantity" : "all",
"class" : "Cd"
},
{
"quantity" : "all",
"class" : "Track"
},
{
"quantity" : "all",
"class" : "Artist"
}
],
"might_have" : {
"fetch" : 0
},
"belongs_to" : {
"fetch" : 0
},
"has_many" : {
"fetch" : 0
}
}