class ActiveStorage::Attached

classes that both provide proxy access to the blob association for a record.
Abstract base class for the concrete ActiveStorage::Attached::One and ActiveStorage::Attached::Many

def create_blob_from(attachable) 

def create_blob_from(attachable)
  case attachable
  when ActiveStorage::Blob
    attachable
  when ActionDispatch::Http::UploadedFile, Rack::Test::UploadedFile
    ActiveStorage::Blob.create_after_upload! \
      io: attachable.open,
      filename: attachable.original_filename,
      content_type: attachable.content_type
  when Hash
    ActiveStorage::Blob.create_after_upload!(attachable)
  when String
    ActiveStorage::Blob.find_signed(attachable)
  else
    nil
  end
end

def initialize(name, record, dependent:) 

def initialize(name, record, dependent:)
  @name, @record, @dependent = name, record, dependent
end