def evercookie_is_set?(key, value = nil)
      if session[Evercookie.hash_name_for_saved].blank?
        false
      elsif value.nil?
        session[Evercookie.hash_name_for_saved][key].present?
      else
        session[Evercookie.hash_name_for_saved][key].present? \
          && session[Evercookie.hash_name_for_saved][key] == value
      end
    end
def evercookie_is_set?(key, value = nil)
      if session[Evercookie.hash_name_for_saved].blank?
        false
      elsif value.nil?
        session[Evercookie.hash_name_for_saved][key].present?
      else
        session[Evercookie.hash_name_for_saved][key].present? \
          && session[Evercookie.hash_name_for_saved][key] == value
      end
    end
Checks whether the evercookie with specific key was defined
 == Examples:
   evercookie_is_set?(:key)
   evercookie_is_set?(:key, :value)