Assistance Requested for Elixir Book Mars Rover Example

The reader Anti_Duehring has encountered an issue while working through 'Elixir Succinctly', a free e-book dedicated to Elixir programming. In Chapter 4, which introduces a sample application for a Mars Rover that utilizes the concepts of GenServer and RegistryHelper, Anti_Duehring found that the source code is missing for two `RegistryHelper` methods: `create_key/1` and `get_pid/1`. The absence of these methods is preventing the compilation and further progression in the book. The reader is reaching out to more experienced Elixir developers for assistance to provide the missing code snippets.