class ActionText::Content

def attachables

content.attachables # => [attachable]
content = ActionText::Content.new(html)
html = %Q()
attachable = ActiveStorage::Blob.first

Extracts +ActionText::Attachable+s from the HTML fragment: 
def attachables
  @attachables ||= attachment_nodes.map do |node|
    ActionText::Attachable.from_node(node)
  end
end