class RuboCop::Cop::Rake::DuplicateTask

def namespaces(node)
  ns = []
  node.each_ancestor(:block) do |block_node|
    send_node = block_node.send_node
    next unless send_node.method?(:namespace)
    name = Helper::TaskName.task_name(send_node)
    ns << name
  end
  ns
end