class ActiveAdmin::Views::ActiveAdminForm

def build(resource, options = {}, &block)
  @resource = resource
  options = options.deep_dup
  options[:builder] ||= ActiveAdmin::FormBuilder
  form_string = helpers.semantic_form_for(resource, options) do |f|
    @form_builder = f
  end
  @opening_tag, @closing_tag = split_string_on(form_string, "</form>")
  instance_eval(&block) if block
  # Rails sets multipart automatically if a file field is present,
  # but the form tag has already been rendered before the block eval.
  if multipart? && !@opening_tag.include?('multipart')
    @opening_tag.sub!(/<form/, '<form enctype="multipart/form-data"')
  end
end