module ActiveJob::Arguments

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