def normalize_open_graph(meta_tags)
      meta_tags = meta_tags.kind_of?(HashWithIndifferentAccess) ? meta_tags.dup : meta_tags.with_indifferent_access
      meta_tags[:og] = meta_tags.delete(:open_graph) if meta_tags.key?(:open_graph)
      meta_tags
    end
def normalize_open_graph(meta_tags)
      meta_tags = meta_tags.kind_of?(HashWithIndifferentAccess) ? meta_tags.dup : meta_tags.with_indifferent_access
      meta_tags[:og] = meta_tags.delete(:open_graph) if meta_tags.key?(:open_graph)
      meta_tags
    end
Converts input hash to HashWithIndifferentAccess and renames :open_graph to :og.

 @param [Hash] meta_tags list of meta tags.
 @return [HashWithIndifferentAccess] normalized meta tags list.