code: def init(id, pubkey, overwrite: false, network: 'test')
        raise "File '#{path}' already exists" if File.exist?(path) && !overwrite
        raise "Invalid network name '#{network}'" unless network =~ /^[a-z]{4,16}$/
        FileUtils.mkdir_p(File.dirname(path))
        IO.write(path, "#{network}\n#{PROTOCOL}\n#{id}\n#{pubkey.to_pub}\n\n")
        @txns.flush
        @head.flush
      end
docs: Creates an empty wallet with the specified ID and public key.