class GraphQL::Schema::RelayClassicMutation

def argument(*args, own_argument: false, **kwargs, &block)
  it = input_type # make sure any inherited arguments are already added to it
  arg = super(*args, **kwargs, &block)
  # This definition might be overriding something inherited;
  # if it is, remove the inherited definition so it's not confused at runtime as having multiple definitions
  prev_args = it.own_arguments[arg.graphql_name]
  case prev_args
  when GraphQL::Schema::Argument
    if prev_args.owner != self
      it.own_arguments.delete(arg.graphql_name)
    end
  when Array
    prev_args.reject! { |a| a.owner != self }
    if prev_args.empty?
      it.own_arguments.delete(arg.graphql_name)
    end
  end
  it.add_argument(arg)
  arg
end