defining a GraphQL mutation in DGraph that adds a node that is of union type within another node - graphql

Question

I am new to GraphQL and Dgraph and have been reading through the manual.
I am following an example in the manual posted here:
https://dgraph.io/docs/graphql/schema/types/#union-type
I am seeking to use a mutation to add a node or list of Nodes and associate them as members acceptable within the addHome input function.
These nodes are however also of type Union and so I need to somehow cast the HomeMember to a Dog and define the category as an animal.
I see someone posted something here but i can't pull the pieces together since the code it suggests appears to already have been generated by DGraph:
https://discuss.dgraph.io/t/union-types-in-graphql/9581
I am unsure but have a feeling I perhaps need to somehow override the input HomeMemberRef which is automatically generated into the schema by DGraph and disable both parrot and human ?
My code so far looks like this:
mutation {
addHome(input: [
{address: "London",
// Here I need to add something a member that casts the
// HomeMember to a Dog, defines the category as an animal and is accepted within
// this addHome input function
}
]) {
home{
address
id
members
}
}
}

Answer 1

Found the answer posted on another page:
https://dgraph.io/docs/graphql/mutations/mutations-overview/
My GraphQL works using this:
mutation {
addHome(input: [
{address: "London",
members: [
{ dogRef: { category: Mammal, breed: "German Shepherd"} },
]
}
]) {
home {
address
members {
... on Dog {
breed
}
... on Parrot {
repeatsWords
}
... on Human {
name
}
}
}
}
}