docs: def run_process(self, slug, inputs):
          """Run a new process from a running process."""
          def export_files(value):
              """Export input files of spawned process."""
              if isinstance(value, str) and os.path.isfile(value):
                  # TODO: Use the protocol to export files and get the
                  # process schema to check field type.
                  print("export {}".format(value))
              elif isinstance(value, dict):
                  for item in value.values():
                      export_files(item)
              elif isinstance(value, list):
                  for item in value:
                      export_files(item)
  
          export_files(inputs)
          print('run {}'.format(json.dumps({'process': slug, 'input': inputs}, separators=(',', ':'))))