class Roda::RodaPlugins::ContentSecurityPolicy::Policy

def header_value
  return @header_value if @header_value
  s = String.new
  @opts.each do |k, vs|
    s << k
    unless vs == true
      vs.each{|v| append_formatted_value(s, v)}
    end
    s << '; '
  end
  @header_value = s
end