serialize_hash_key

# File activejob/lib/active_job/arguments.rb, line 123
      def serialize_hash_key(key)
        case key
        when *RESERVED_KEYS
          raise SerializationError.new("Can't serialize a Hash with reserved key #{key.inspect}")
        when String, Symbol
          key.to_s
        else
          raise SerializationError.new("Only string and symbol hash keys may be serialized as job arguments, but #{key.inspect} is a #{key.class}")
        end
      end