Create/append to page data from custom Liquid tag

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1

I’ve created a custom Liquid tag. I want this tag to create (or append) an array called facilities. My code is copied below. It seems to do this just fine as evidenced by the print statement. However, when I try to access the data in a page or post with {{ page.facilities }} I get a null value returned. It seems the facilities array isn’t kept.

How can I keep my facilities array?

module Jekyll
  class Facility < Liquid::Tag
    def initialize(tag_name, input, tokens)
      super
      @name = input.strip
    end

    def render(context)
      begin
        page = context.environments.first['page']

        @tags = page['tags']
        @tags.append(@name) unless @tags.include?(@name)

        page['facilities'] = [] unless page.key?('facilities')
        @facilities = page['facilities']
        print( "Facilities: #{@facilities}")
        @facilities << @name  unless @facilities.include?(@name)

    end
  end
end

Liquid::Template.register_tag('facility', Jekyll::Facility)