def property_key(prop)
      prop_key = prop.name.join
      prop_value = value_as_string(prop.value.first)

      # Differentiate between values for different vendor prefixes
      prop_value.to_s.scan(/^(-[^-]+-.+)/) do |vendor_keyword|
        prop_key << vendor_keyword.first
      end

      prop_key
    end
def property_key(prop)
      prop_key = prop.name.join
      prop_value = value_as_string(prop.value.first)

      # Differentiate between values for different vendor prefixes
      prop_value.to_s.scan(/^(-[^-]+-.+)/) do |vendor_keyword|
        prop_key << vendor_keyword.first
      end

      prop_key
    end
Returns a key identifying the bucket this property and value correspond to
 for purposes of uniqueness.